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  • I am trying to insert value from combo box to database !! but this is not working

    - by user3675488
    At first I have taken some string in which I am trying to save the input values of textboxs and there is a combo box, I am trying to save the input value of the combo box to database, but this following code is unable to do that !!! what is the prob please help me. private void OK_Click(object sender, EventArgs e) { string sTxtcmpnyName = ""; string sTxtcmpnyAdd = ""; string sPhoneno = ""; string sTxtFax = ""; string sPanNo = ""; string sTxtTin = ""; string sTax = ""; string sAccYr = ""; string sComboSt = ""; foreach (Control c in this.Controls) ////*Adding Validation to the textbox.*// // Here the control is entered into GroupBox Grpcmp where c is denoting the name of the control into the groupbox. { // c1 is another control which denotes the textboxes under the GroupBox Grpcmp. foreach (Control c1 in c.Controls) { /////Now this following code snippets reperesents that the name of the company should not be blank. if (c1 is TextBox == true) // simpler that what you've done there { TextBox temp = (TextBox)c1; //The control is entering into Txtcompany. if (temp.Name == "Txtcompanyname") { //Condition checking is the TextBox is empty or Null then the following message will be shown. if ((temp.Text == "") || (temp.Text == "NULL")) { MessageBox.Show("Company Name should not be Blank"); } sTxtcmpnyName = temp.Text; } else if (c1.Name == "TxtcompanyAddress") { sTxtcmpnyAdd = c1.Text; } else if (c1.Name == "Txtphoneno") { sPhoneno = c1.Text; } else if (c1.Name == "TxtFax ") { sTxtFax = c1.Text; } else if (c1.Name == "Txtpanno") { sPanNo = c1.Text; } else if (c1.Name == "TxtTin") { sTxtTin = c1.Text; } else if (c1.Name == "Txtservicetax") { sTax = c1.Text; } //Now I am converting the TxtAcYr into Date format. //For this purpose two conditions are checked first. //First If the TextBox TxtAcYr is Null or empty it will show the message to enter the accountyear!! //Second If the length of the TextBox TxtAcYr is less than 10, it will again generate a message The date format should be in DD/MM/YYYY // Then the value of the use input will be picked using a For loop. if (c1.Name == "TxtAcYr") { sAccYr = c1.Text; //Here a string is taken named as yearlength and the value of the TxtAcYr is assigned to it by using control c1. //Condition Checking If the TextBox TxtAcYr is Null or empty it will show the message to enter the accountyear!! if ((c1.Text == "") || (c1.Text == "NULL")) { MessageBox.Show("Account Year should be entered!!"); } //Condition 2 is checking. Here the length of the string yearlength is whether equals to 10 or not is checked. //Because there are total 10 characters in Date Format along with special character. else // MessageBox.Show(yearlength.Length.ToString()); if (sAccYr.Length != 10) { MessageBox.Show("The Data Format DD-MM-YYYY"); } //Now the value of user will be picked by using the code snippets. else { //A string named as JK is taken for further use. String JK = ""; //This following loop is initiated to pick the user input. //The loop will check wheather the value of i is less than the length of string yearlength or not. //If Yes then it will go further. for (int i = 0; i < sAccYr.Length; i++) { //This condition is checking special characters. //The positions of special characters(Here '-') are placed at 2nd and 5th numbers. //So, the value of i can not be equals to 2 && 5. if ((i != 2) && (i != 5)) { //The new of value of year length i is assinged to the variable JK. JK = JK + sAccYr[i]; } //If the value of i is equals to 1, then enter the following. if (i == 1) { //*Should add the function of TOInt32* // If ToInt32(JK)>= the maximum length of days of a month then the following alert message will be shown. if (Convert.ToInt32(JK) >= 32) { MessageBox.Show("The Data Format DD-MM-YYYY"); } //**Comment should be added.** JK = ""; } else //If the value of i is equals to 4, then enter the following. if (i == 4) { //*Should add the function of TOInt32* // If ToInt32(JK)>= the maximum length of month then the following alert message will be shown. if (Convert.ToInt32(JK) >= 13) { MessageBox.Show("The Data Format DD-MM-YYYY"); } JK = ""; } } } } } else if (c1.Name == "state_cmb") { //sTxttate = c1.Text.ToString(); sComboSt = c1.Text; MessageBox.Show(c1.Text); } } } //////DATABASE CONNECTION///// try { SqlConnection conn = new SqlConnection(); SqlCommand cmd = new SqlCommand(); conn.ConnectionString = ("Data Source =192.168.0.2 ;database= Mee_Company; Persist Security Info =true; User ID =sa;Password = soso654321@"); conn.Open(); cmd.CommandText = ("INSERT INTO CompanyMaster(CompanyName,Address,State,Phone,Fax,PAN,TIN,STAX,AccountsYear)values('" + sTxtcmpnyName + "','" + sTxtcmpnyAdd + "','" + sComboSt + "','" + sPhoneno + "','" + sTxtFax + "','" + sPanNo + "','" + sTxtTin + "','" + sTax + "','" + sAccYr + "')"); //('" + sTxtcmpnyName + "', '" + TxtcompanyAddress.Text + "', '" + Txtphoneno.Text + "', '" + TxtFax.Text + "', '" + Txtservicetax.Text + "','" + TxtAcYr.Text + "')"); cmd.Connection = conn; cmd.ExecuteNonQuery(); conn.Close(); //cmd.Parameters.AddWithValue } catch (Exception ee) { MessageBox.Show(ee.ToString()); } } //An event is created here so that when the user will click on the Cancel Button, the Form will be closed. private void BtmCancle_Click(object sender, EventArgs e) { //this means the form. this.Close(); } //Another Event is created here named as TxtAcYr_KeyPress. //It is for making the TextBox TxtAcYr only allowance of numeric input along with special character '-'. private void TxtAcYr_KeyPress(object sender, KeyPressEventArgs e) { //If the input is number or '-' is checked //And also the backspace and delete option is enabled here. if (char.IsNumber(e.KeyChar) || e.KeyChar == (char)Keys.Back || e.KeyChar == (char)Keys.Delete || e.KeyChar == '-') { e.Handled = false; //ok } else { e.Handled = true; //not ok } }

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  • Point of contact of 2 OBBs?

    - by Milo
    I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the point of contact when I hit a wall. Here is my OBB class: public class OBB2D { private Vector2D projVec = new Vector2D(); private static Vector2D projAVec = new Vector2D(); private static Vector2D projBVec = new Vector2D(); private static Vector2D tempNormal = new Vector2D(); private Vector2D deltaVec = new Vector2D(); // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(float centerx, float centery, float w, float h, float angle) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(centerx,centery,w,h,angle); } public OBB2D(float left, float top, float width, float height) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(left + (width / 2), top + (height / 2),width,height,0.0f); } public void set(float centerx,float centery,float w, float h,float angle) { float vxx = (float)Math.cos(angle); float vxy = (float)Math.sin(angle); float vyx = (float)-Math.sin(angle); float vyy = (float)Math.cos(angle); vxx *= w / 2; vxy *= (w / 2); vyx *= (h / 2); vyy *= (h / 2); corner[0].x = centerx - vxx - vyx; corner[0].y = centery - vxy - vyy; corner[1].x = centerx + vxx - vyx; corner[1].y = centery + vxy - vyy; corner[2].x = centerx + vxx + vyx; corner[2].y = centery + vxy + vyy; corner[3].x = centerx - vxx + vyx; corner[3].y = centery - vxy + vyy; this.center.x = centerx; this.center.y = centery; this.angle = angle; computeAxes(); extents.x = w / 2; extents.y = h / 2; computeBoundingRect(); } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0].x = corner[1].x - corner[0].x; axis[0].y = corner[1].y - corner[0].y; axis[1].x = corner[3].x - corner[0].x; axis[1].y = corner[3].y - corner[0].y; // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { float l = axis[a].length(); float ll = l * l; axis[a].x = axis[a].x / ll; axis[a].y = axis[a].y / ll; origin[a] = corner[0].dot(axis[a]); } } public void computeBoundingRect() { boundingRect.left = JMath.min(JMath.min(corner[0].x, corner[3].x), JMath.min(corner[1].x, corner[2].x)); boundingRect.top = JMath.min(JMath.min(corner[0].y, corner[1].y),JMath.min(corner[2].y, corner[3].y)); boundingRect.right = JMath.max(JMath.max(corner[1].x, corner[2].x), JMath.max(corner[0].x, corner[3].x)); boundingRect.bottom = JMath.max(JMath.max(corner[2].y, corner[3].y),JMath.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(rect.centerX(),rect.centerY(),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } public void moveTo(float centerx, float centery) { float cx,cy; cx = center.x; cy = center.y; deltaVec.x = centerx - cx; deltaVec.y = centery - cy; for (int c = 0; c < 4; ++c) { corner[c].x += deltaVec.x; corner[c].y += deltaVec.y; } boundingRect.left += deltaVec.x; boundingRect.top += deltaVec.y; boundingRect.right += deltaVec.x; boundingRect.bottom += deltaVec.y; this.center.x = centerx; this.center.y = centery; computeAxes(); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center.x,center.y,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center.x,center.y,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } public static float distance(float ax, float ay,float bx, float by) { if (ax < bx) return bx - ay; else return ax - by; } public Vector2D project(float ax, float ay) { projVec.x = Float.MAX_VALUE; projVec.y = Float.MIN_VALUE; for (int i = 0; i < corner.length; ++i) { float dot = Vector2D.dot(corner[i].x,corner[i].y,ax,ay); projVec.x = JMath.min(dot, projVec.x); projVec.y = JMath.max(dot, projVec.y); } return projVec; } public Vector2D getCorner(int c) { return corner[c]; } public int getNumCorners() { return corner.length; } public static float collisionResponse(OBB2D a, OBB2D b, Vector2D outNormal) { float depth = Float.MAX_VALUE; for (int i = 0; i < a.getNumCorners() + b.getNumCorners(); ++i) { Vector2D edgeA; Vector2D edgeB; if(i >= a.getNumCorners()) { edgeA = b.getCorner((i + b.getNumCorners() - 1) % b.getNumCorners()); edgeB = b.getCorner(i % b.getNumCorners()); } else { edgeA = a.getCorner((i + a.getNumCorners() - 1) % a.getNumCorners()); edgeB = a.getCorner(i % a.getNumCorners()); } tempNormal.x = edgeB.x -edgeA.x; tempNormal.y = edgeB.y - edgeA.y; tempNormal.normalize(); projAVec.equals(a.project(tempNormal.x,tempNormal.y)); projBVec.equals(b.project(tempNormal.x,tempNormal.y)); float distance = OBB2D.distance(projAVec.x, projAVec.y,projBVec.x,projBVec.y); if (distance > 0.0f) { return 0.0f; } else { float d = Math.abs(distance); if (d < depth) { depth = d; outNormal.equals(tempNormal); } } } float dx,dy; dx = b.getCenter().x - a.getCenter().x; dy = b.getCenter().y - a.getCenter().y; float dot = Vector2D.dot(dx,dy,outNormal.x,outNormal.y); if(dot > 0) { outNormal.x = -outNormal.x; outNormal.y = -outNormal.y; } return depth; } public Vector2D getMoveDeltaVec() { return deltaVec; } }; Thanks!

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  • C#/.NET Little Wonders: The Nullable static class

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Today we’re going to look at an interesting Little Wonder that can be used to mitigate what could be considered a Little Pitfall.  The Little Wonder we’ll be examining is the System.Nullable static class.  No, not the System.Nullable<T> class, but a static helper class that has one useful method in particular that we will examine… but first, let’s look at the Little Pitfall that makes this wonder so useful. Little Pitfall: Comparing nullable value types using <, >, <=, >= Examine this piece of code, without examining it too deeply, what’s your gut reaction as to the result? 1: int? x = null; 2:  3: if (x < 100) 4: { 5: Console.WriteLine("True, {0} is less than 100.", 6: x.HasValue ? x.ToString() : "null"); 7: } 8: else 9: { 10: Console.WriteLine("False, {0} is NOT less than 100.", 11: x.HasValue ? x.ToString() : "null"); 12: } Your gut would be to say true right?  It would seem to make sense that a null integer is less than the integer constant 100.  But the result is actually false!  The null value is not less than 100 according to the less-than operator. It looks even more outrageous when you consider this also evaluates to false: 1: int? x = null; 2:  3: if (x < int.MaxValue) 4: { 5: // ... 6: } So, are we saying that null is less than every valid int value?  If that were true, null should be less than int.MinValue, right?  Well… no: 1: int? x = null; 2:  3: // um... hold on here, x is NOT less than min value? 4: if (x < int.MinValue) 5: { 6: // ... 7: } So what’s going on here?  If we use greater than instead of less than, we see the same little dilemma: 1: int? x = null; 2:  3: // once again, null is not greater than anything either... 4: if (x > int.MinValue) 5: { 6: // ... 7: } It turns out that four of the comparison operators (<, <=, >, >=) are designed to return false anytime at least one of the arguments is null when comparing System.Nullable wrapped types that expose the comparison operators (short, int, float, double, DateTime, TimeSpan, etc.).  What’s even odder is that even though the two equality operators (== and !=) work correctly, >= and <= have the same issue as < and > and return false if both System.Nullable wrapped operator comparable types are null! 1: DateTime? x = null; 2: DateTime? y = null; 3:  4: if (x <= y) 5: { 6: Console.WriteLine("You'd think this is true, since both are null, but it's not."); 7: } 8: else 9: { 10: Console.WriteLine("It's false because <=, <, >, >= don't work on null."); 11: } To make matters even more confusing, take for example your usual check to see if something is less than, greater to, or equal: 1: int? x = null; 2: int? y = 100; 3:  4: if (x < y) 5: { 6: Console.WriteLine("X is less than Y"); 7: } 8: else if (x > y) 9: { 10: Console.WriteLine("X is greater than Y"); 11: } 12: else 13: { 14: // We fall into the "equals" assumption, but clearly null != 100! 15: Console.WriteLine("X is equal to Y"); 16: } Yes, this code outputs “X is equal to Y” because both the less-than and greater-than operators return false when a Nullable wrapped operator comparable type is null.  This violates a lot of our assumptions because we assume is something is not less than something, and it’s not greater than something, it must be equal.  So keep in mind, that the only two comparison operators that work on Nullable wrapped types where at least one is null are the equals (==) and not equals (!=) operators: 1: int? x = null; 2: int? y = 100; 3:  4: if (x == y) 5: { 6: Console.WriteLine("False, x is null, y is not."); 7: } 8:  9: if (x != y) 10: { 11: Console.WriteLine("True, x is null, y is not."); 12: } Solution: The Nullable static class So we’ve seen that <, <=, >, and >= have some interesting and perhaps unexpected behaviors that can trip up a novice developer who isn’t expecting the kinks that System.Nullable<T> types with comparison operators can throw.  How can we easily mitigate this? Well, obviously, you could do null checks before each check, but that starts to get ugly: 1: if (x.HasValue) 2: { 3: if (y.HasValue) 4: { 5: if (x < y) 6: { 7: Console.WriteLine("x < y"); 8: } 9: else if (x > y) 10: { 11: Console.WriteLine("x > y"); 12: } 13: else 14: { 15: Console.WriteLine("x == y"); 16: } 17: } 18: else 19: { 20: Console.WriteLine("x > y because y is null and x isn't"); 21: } 22: } 23: else if (y.HasValue) 24: { 25: Console.WriteLine("x < y because x is null and y isn't"); 26: } 27: else 28: { 29: Console.WriteLine("x == y because both are null"); 30: } Yes, we could probably simplify this logic a bit, but it’s still horrendous!  So what do we do if we want to consider null less than everything and be able to properly compare Nullable<T> wrapped value types? The key is the System.Nullable static class.  This class is a companion class to the System.Nullable<T> class and allows you to use a few helper methods for Nullable<T> wrapped types, including a static Compare<T>() method of the. What’s so big about the static Compare<T>() method?  It implements an IComparer compatible comparison on Nullable<T> types.  Why do we care?  Well, if you look at the MSDN description for how IComparer works, you’ll read: Comparing null with any type is allowed and does not generate an exception when using IComparable. When sorting, null is considered to be less than any other object. This is what we probably want!  We want null to be less than everything!  So now we can change our logic to use the Nullable.Compare<T>() static method: 1: int? x = null; 2: int? y = 100; 3:  4: if (Nullable.Compare(x, y) < 0) 5: { 6: // Yes! x is null, y is not, so x is less than y according to Compare(). 7: Console.WriteLine("x < y"); 8: } 9: else if (Nullable.Compare(x, y) > 0) 10: { 11: Console.WriteLine("x > y"); 12: } 13: else 14: { 15: Console.WriteLine("x == y"); 16: } Summary So, when doing math comparisons between two numeric values where one of them may be a null Nullable<T>, consider using the System.Nullable.Compare<T>() method instead of the comparison operators.  It will treat null less than any value, and will avoid logic consistency problems when relying on < returning false to indicate >= is true and so on. Tweet   Technorati Tags: C#,C-Sharp,.NET,Little Wonders,Little Pitfalls,Nulalble

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  • Why unhandled exceptions are useful

    - by Simon Cooper
    It’s the bane of most programmers’ lives – an unhandled exception causes your application or webapp to crash, an ugly dialog gets displayed to the user, and they come complaining to you. Then, somehow, you need to figure out what went wrong. Hopefully, you’ve got a log file, or some other way of reporting unhandled exceptions (obligatory employer plug: SmartAssembly reports an application’s unhandled exceptions straight to you, along with the entire state of the stack and variables at that point). If not, you have to try and replicate it yourself, or do some psychic debugging to try and figure out what’s wrong. However, it’s good that the program crashed. Or, more precisely, it is correct behaviour. An unhandled exception in your application means that, somewhere in your code, there is an assumption that you made that is actually invalid. Coding assumptions Let me explain a bit more. Every method, every line of code you write, depends on implicit assumptions that you have made. Take this following simple method, that copies a collection to an array and includes an item if it isn’t in the collection already, using a supplied IEqualityComparer: public static T[] ToArrayWithItem( ICollection<T> coll, T obj, IEqualityComparer<T> comparer) { // check if the object is in collection already // using the supplied comparer foreach (var item in coll) { if (comparer.Equals(item, obj)) { // it's in the collection already // simply copy the collection to an array // and return it T[] array = new T[coll.Count]; coll.CopyTo(array, 0); return array; } } // not in the collection // copy coll to an array, and add obj to it // then return it T[] array = new T[coll.Count+1]; coll.CopyTo(array, 0); array[array.Length-1] = obj; return array; } What’s all the assumptions made by this fairly simple bit of code? coll is never null comparer is never null coll.CopyTo(array, 0) will copy all the items in the collection into the array, in the order defined for the collection, starting at the first item in the array. The enumerator for coll returns all the items in the collection, in the order defined for the collection comparer.Equals returns true if the items are equal (for whatever definition of ‘equal’ the comparer uses), false otherwise comparer.Equals, coll.CopyTo, and the coll enumerator will never throw an exception or hang for any possible input and any possible values of T coll will have less than 4 billion items in it (this is a built-in limit of the CLR) array won’t be more than 2GB, both on 32 and 64-bit systems, for any possible values of T (again, a limit of the CLR) There are no threads that will modify coll while this method is running and, more esoterically: The C# compiler will compile this code to IL according to the C# specification The CLR and JIT compiler will produce machine code to execute the IL on the user’s computer The computer will execute the machine code correctly That’s a lot of assumptions. Now, it could be that all these assumptions are valid for the situations this method is called. But if this does crash out with an exception, or crash later on, then that shows one of the assumptions has been invalidated somehow. An unhandled exception shows that your code is running in a situation which you did not anticipate, and there is something about how your code runs that you do not understand. Debugging the problem is the process of learning more about the new situation and how your code interacts with it. When you understand the problem, the solution is (usually) obvious. The solution may be a one-line fix, the rewrite of a method or class, or a large-scale refactoring of the codebase, but whatever it is, the fix for the crash will incorporate the new information you’ve gained about your own code, along with the modified assumptions. When code is running with an assumption or invariant it depended on broken, then the result is ‘undefined behaviour’. Anything can happen, up to and including formatting the entire disk or making the user’s computer sentient and start doing a good impression of Skynet. You might think that those can’t happen, but at Halting problem levels of generality, as soon as an assumption the code depended on is broken, the program can do anything. That is why it’s important to fail-fast and stop the program as soon as an invariant is broken, to minimise the damage that is done. What does this mean in practice? To start with, document and check your assumptions. As with most things, there is a level of judgement required. How you check and document your assumptions depends on how the code is used (that’s some more assumptions you’ve made), how likely it is a method will be passed invalid arguments or called in an invalid state, how likely it is the assumptions will be broken, how expensive it is to check the assumptions, and how bad things are likely to get if the assumptions are broken. Now, some assumptions you can assume unless proven otherwise. You can safely assume the C# compiler, CLR, and computer all run the method correctly, unless you have evidence of a compiler, CLR or processor bug. You can also assume that interface implementations work the way you expect them to; implementing an interface is more than simply declaring methods with certain signatures in your type. The behaviour of those methods, and how they work, is part of the interface contract as well. For example, for members of a public API, it is very important to document your assumptions and check your state before running the bulk of the method, throwing ArgumentException, ArgumentNullException, InvalidOperationException, or another exception type as appropriate if the input or state is wrong. For internal and private methods, it is less important. If a private method expects collection items in a certain order, then you don’t necessarily need to explicitly check it in code, but you can add comments or documentation specifying what state you expect the collection to be in at a certain point. That way, anyone debugging your code can immediately see what’s wrong if this does ever become an issue. You can also use DEBUG preprocessor blocks and Debug.Assert to document and check your assumptions without incurring a performance hit in release builds. On my coding soapbox… A few pet peeves of mine around assumptions. Firstly, catch-all try blocks: try { ... } catch { } A catch-all hides exceptions generated by broken assumptions, and lets the program carry on in an unknown state. Later, an exception is likely to be generated due to further broken assumptions due to the unknown state, causing difficulties when debugging as the catch-all has hidden the original problem. It’s much better to let the program crash straight away, so you know where the problem is. You should only use a catch-all if you are sure that any exception generated in the try block is safe to ignore. That’s a pretty big ask! Secondly, using as when you should be casting. Doing this: (obj as IFoo).Method(); or this: IFoo foo = obj as IFoo; ... foo.Method(); when you should be doing this: ((IFoo)obj).Method(); or this: IFoo foo = (IFoo)obj; ... foo.Method(); There’s an assumption here that obj will always implement IFoo. If it doesn’t, then by using as instead of a cast you’ve turned an obvious InvalidCastException at the point of the cast that will probably tell you what type obj actually is, into a non-obvious NullReferenceException at some later point that gives you no information at all. If you believe obj is always an IFoo, then say so in code! Let it fail-fast if not, then it’s far easier to figure out what’s wrong. Thirdly, document your assumptions. If an algorithm depends on a non-trivial relationship between several objects or variables, then say so. A single-line comment will do. Don’t leave it up to whoever’s debugging your code after you to figure it out. Conclusion It’s better to crash out and fail-fast when an assumption is broken. If it doesn’t, then there’s likely to be further crashes along the way that hide the original problem. Or, even worse, your program will be running in an undefined state, where anything can happen. Unhandled exceptions aren’t good per-se, but they give you some very useful information about your code that you didn’t know before. And that can only be a good thing.

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  • Get information about AutocompleteTextView from resulting AutoCompleteTextView$DropDownListView

    - by Stev_k
    I'm using 3 AutocompleteTextViews to suggest entries from a database. I subclassed AutocompleteTextView to handle setting the default text to null when clicked and setting back to the default instructions if moved away and nothing is entered. I was using a SimpleCursorAdapter to bind to the view, but I discovered that there was no way I could get the id of the AutocompleteTextView from an OnItemClickListener, which I needed to put additional information from the selected row in a variable depending on which AutocompleteTextView it was from. All I could access was the AutoCompleteTextView$DropDownListView, which is an undocumented inner class that appears to offer no real functionality. Neither was there a way to go up the view hierarchy to get the original AutocompleteTextView. So I subclassed SimpleCursorAdapter and added an int to the constructor to identify which AutocompleteTextView the adapter was from, and I was able to access this from the view passed into OnItemClick(). So, although my solution works fine, I wonder if it is possible to get the id of an AutocompleteTextView from its DropDownListView? I am also using another database query which gets the id from the OnItemClick and then looks up the data for that item, because I couldn't find a way of converting more than one column to a string. Should I be using CursorAdapter for this, to save initiating another query? Oh, and another thing, do I need a database cursor initially (all_cursor) when all I'm doing is filtering on it to get a new cursor? Seems like overkill. Activity .... dbse.openDataBase(); Cursor all_Cursor = dbse.autocomplete_query(); startManagingCursor(all_Cursor); String[] from_all = new String[]{DbAdapter.KEY_NAME}; int[] to_all = new int[] {android.R.id.text1}; from_adapt = new AutocompleteAdapter(FROM_DBADAPTER, this,android.R.layout.simple_dropdown_item_1line, all_Cursor, from_all, to_all); from_adapt.setStringConversionColumn(1); from_adapt.setFilterQueryProvider(this); to_adapt = new AutocompleteAdapter(TO_DBADAPTER, this,android.R.layout.simple_dropdown_item_1line, all_Cursor, from_all, to_all); to_adapt.setStringConversionColumn(1); to_adapt.setFilterQueryProvider(this); from_auto_complete = (Autocomplete) findViewById(R.id.entry_from); from_auto_complete.setAdapter(from_adapt); from_auto_complete.setOnItemClickListener(this); to_auto_complete = (Autocomplete) findViewById(R.id.entry_to); to_auto_complete.setAdapter(to_adapt); to_auto_complete.setOnItemClickListener(this); public void onItemClick (AdapterView<?> parent, View view, int position, long id) { Cursor selected_row_cursor = dbse.data_from_id(id); selected_row_cursor.moveToFirst(); String lat = selected_row_cursor.getString(1); String lon = selected_row_cursor.getString(2); int source = ((AutocompleteAdapter) parent.getAdapter()).getSource(); Autocomplete class: public class Autocomplete extends AutoCompleteTextView implements OnTouchListener,OnFocusChangeListener{ String textcontent; Context mycontext = null; int viewid = this.getId(); public Autocomplete(Context context, AttributeSet attrs) { super(context, attrs); textcontent = this.getText().toString(); mycontext = context; this.setOnFocusChangeListener(this); this.setOnTouchListener(this); } public boolean onTouch(View v, MotionEvent event) { if (textcontent.equals(mycontext.getString(R.string.from_textbox)) | textcontent.equals(mycontext.getString(R.string.to_textbox)) | textcontent.equals(mycontext.getString(R.string.via_textbox))) { this.setText(""); } return false; } public void onFocusChange(View v, boolean hasFocus) { if (hasFocus == false) { int a = this.getText().length(); if (a == 0){ if (viewid == R.id.entry_from) {this.setText(R.string.from_textbox);} if (viewid == R.id.entry_to) {this.setText(R.string.to_textbox);} if (viewid == R.id.entry_via) {this.setText(R.string.via_textbox);} } } } } Adapter: public class AutocompleteAdapter extends SimpleCursorAdapter { int source; public AutocompleteAdapter(int query_source, Context context, int layout, Cursor c, String[] from, int[] to) { super(context, layout, c, from, to); source = query_source; } public int getSource() { return source; } } sorry that's a lot of code! Thanks for your help. Stephen

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  • Is it possible to specify a generic constraint for a type parameter to be convertible FROM another t

    - by fostandy
    Suppose I write a library with the following: public class Bar { /* ... */ } public class SomeWeirdClass<T> where T : ??? { public T BarMaker(Bar b) { // ... play with b T t = (T)b return (T) b; } } Later, I expect users to use my library by defining their own types which are convertible to Bar and using the SomeWeirdClass 'factory'. public class Foo { public static explicit operator Foo(Bar f) { return new Bar(); } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } this will compile if i set where T : Foo but the problem is that I don't know about Foo at the library's compile time, and I actually want something more like where T : some class that can be instantiated, given a Bar Is this possible? From my limited knowledge it does not seem to be, but the ingenuity of the .NET framework and its users always surprises me... This may or not be related to the idea of static interface methods - at least, I can see the value in being able to specify the presence of factory methods to create objects (similar to the same way that you can already perform where T : new()) edit: Solution - thanks to Nick and bzIm - For other readers I'll provide a completed solution as I understand it: edit2: This solution requires Foo to expose a public default constructor. For an even stupider better solution that does not require this see the very bottom of this post. public class Bar {} public class SomeWeirdClass<T> where T : IConvertibleFromBar<T>, new() { public T BarMaker(Bar b) { T t = new T(); t.Convert(b); return t; } } public interface IConvertibleFromBar<T> { T Convert(Bar b); } public class Foo : IConvertibleFromBar<Foo> { public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } edit2: Solution 2: Create a type convertor factory to use: #region library defined code public class Bar {} public class SomeWeirdClass<T, TFactory> where TFactory : IConvertorFactory<Bar, T>, new() { private static TFactory convertor = new TFactory(); public T BarMaker(Bar b) { return convertor.Convert(b); } } public interface IConvertorFactory<TFrom, TTo> { TTo Convert(TFrom from); } #endregion #region user defined code public class BarToFooConvertor : IConvertorFactory<Bar, Foo> { public Foo Convert(Bar from) { return (Foo) from; } } public class Foo { public Foo(int a) {} public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } #endregion public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo, BarToFooConvertor> weird = new SomeWeirdClass<Foo, BarToFooConvertor>(); Foo f = weird.BarMaker(b); } }

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  • Is it possible to specify a generic constraint for a type parameter to be convertible FROM another t

    - by fostandy
    Suppose I write a library with the following: public class Bar { /* ... */ } public class SomeWeirdClass<T> where T : ??? { public T BarMaker(Bar b) { // ... play with b T t = (T)b return (T) b; } } Later, I expect users to use my library by defining their own types which are convertible to Bar and using the SomeWeirdClass 'factory'. public class Foo { public static explicit operator Foo(Bar f) { return new Bar(); } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } this will compile if i set where T : Foo but the problem is that I don't know about Foo at the library's compile time, and I actually want something more like where T : some class that can be instantiated, given a Bar Is this possible? From my limited knowledge it does not seem to be, but the ingenuity of the .NET framework and its users always surprises me... This may or not be related to the idea of static interface methods - at least, I can see the value in being able to specify the presence of factory methods to create objects (similar to the same way that you can already perform where T : new()) edit: Solution - thanks to Nick and bzIm - For other readers I'll provide a completed solution as I understand it: edit2: This solution requires Foo to expose a public default constructor. For an even stupider better solution that does not require this see the very bottom of this post. public class Bar {} public class SomeWeirdClass<T> where T : IConvertibleFromBar<T>, new() { public T BarMaker(Bar b) { T t = new T(); t.Convert(b); return t; } } public interface IConvertibleFromBar<T> { T Convert(Bar b); } public class Foo : IConvertibleFromBar<Foo> { public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } edit2: Solution 2: Create a type convertor factory to use: #region library defined code public class Bar {} public class SomeWeirdClass<T, TFactory> where TFactory : IConvertorFactory<Bar, T>, new() { private static TFactory convertor = new TFactory(); public T BarMaker(Bar b) { return convertor.Convert(b); } } public interface IConvertorFactory<TFrom, TTo> { TTo Convert(TFrom from); } #endregion #region user defined code public class BarToFooConvertor : IConvertorFactory<Bar, Foo> { public Foo Convert(Bar from) { return (Foo) from; } } public class Foo { public Foo(int a) {} public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } #endregion public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo, BarToFooConvertor> weird = new SomeWeirdClass<Foo, BarToFooConvertor>(); Foo f = weird.BarMaker(b); } }

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  • simple C++ hash_set example

    - by celil
    I am new to C++ and STL. I am stuck with the following simple example of a hash set storing custom data structures: #include <iostream> #include <ext/hash_set> using namespace std; using namespace __gnu_cxx; struct trip { int trip_id; int delta_n; int delta_secs; trip(int trip_id, int delta_n, int delta_secs){ this->trip_id = trip_id; this->delta_n = delta_n; this->delta_secs = delta_secs; } }; struct hash_trip { size_t operator()(const trip t) { hash<int> H; return H(t.trip_id); } }; struct eq_trip { bool operator()(const trip t1, const trip t2) { return (t1.trip_id==t2.trip_id) && (t1.delta_n==t2.delta_n) && (t1.delta_secs==t2.delta_secs); } }; int main() { hash_set<trip, hash_trip, eq_trip> trips; trip t = trip(3,2,-1); trip t1 = trip(3,2,0); trips.insert(t); } when I try to compile it, I get the following error message: /usr/include/c++/4.2.1/ext/hashtable.h: In member function ‘size_t __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num_key(const _Key&, size_t) const [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’: /usr/include/c++/4.2.1/ext/hashtable.h:599: instantiated from ‘size_t __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num(const _Val&, size_t) const [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ /usr/include/c++/4.2.1/ext/hashtable.h:1006: instantiated from ‘void __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::resize(size_t) [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ /usr/include/c++/4.2.1/ext/hashtable.h:437: instantiated from ‘std::pair<__gnu_cxx::_Hashtable_iterator<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>, bool> __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::insert_unique(const _Val&) [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ /usr/include/c++/4.2.1/ext/hash_set:197: instantiated from ‘std::pair<typename __gnu_cxx::hashtable<_Value, _Value, _HashFcn, std::_Identity<_Value>, _EqualKey, _Alloc>::const_iterator, bool> __gnu_cxx::hash_set<_Value, _HashFcn, _EqualKey, _Alloc>::insert(const typename __gnu_cxx::hashtable<_Value, _Value, _HashFcn, std::_Identity<_Value>, _EqualKey, _Alloc>::value_type&) [with _Value = trip, _HashFcn = hash_trip, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ try.cpp:45: instantiated from here /usr/include/c++/4.2.1/ext/hashtable.h:595: error: passing ‘const hash_trip’ as ‘this’ argument of ‘size_t hash_trip::operator()(trip)’ discards qualifiers What am I doing wrong?

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  • Need help with BOOST_FOREACH/compiler bug

    - by Jacek Lawrynowicz
    I know that boost or compiler should be last to blame, but I can't see another explanation here. I'm using msvc 2008 SP1 and boost 1.43. In the following code snippet execution never leaves third BOOST_FOREACH loop typedef Graph<unsigned, unsigned>::VertexIterator Iter; Graph<unsigned, unsigned> g; g.createVertex(0x66); // works fine Iter it = g.getVertices().first, end = g.getVertices().second; for(; it != end; ++it) ; // fine std::pair<Iter, Iter> p = g.getVertices(); BOOST_FOREACH(unsigned handle, p) ; // fine unsigned vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; // oops, infinite loop vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; // ... last block repeated 7 times Iterator code: class Iterator : public boost::iterator_facade<Iterator, unsigned const, boost::bidirectional_traversal_tag> { public: Iterator() : list(NULL), handle(INVALID_ELEMENT_HANDLE) {} explicit Iterator(const VectorElementsList &list, unsigned handle = INVALID_ELEMENT_HANDLE) : list(&list), handle(handle) {} friend std::ostream& operator<<(std::ostream &s, const Iterator &it) { s << "[list: " << it.list <<", handle: " << it.handle << "]"; return s; } private: friend class boost::iterator_core_access; void increment() { handle = list->getNext(handle); } void decrement() { handle = list->getPrev(handle); } unsigned const& dereference() const { return handle; } bool equal(Iterator const& other) const { return handle == other.handle && list == other.list; } const VectorElementsList<T> *list; unsigned handle; }; Some ASM fun: vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) // initialization 013E1369 mov edi,dword ptr [___defaultmatherr+8 (13E5034h)] // end iterator handle: 0xFFFFFFFF 013E136F mov ebp,dword ptr [esp+0ACh] // begin iterator handle: 0x0 013E1376 lea esi,[esp+0A8h] // begin iterator list pointer 013E137D mov ebx,esi 013E137F nop // forever loop begin 013E1380 cmp ebp,edi 013E1382 jne main+238h (13E1388h) 013E1384 cmp ebx,esi 013E1386 je main+244h (13E1394h) 013E1388 lea eax,[esp+18h] 013E138C push eax // here iterator is incremented in ram 013E138D call boost::iterator_facade<detail::VectorElementsList<Graph<unsigned int,unsigned int>::VertexWrapper>::Iterator,unsigned int const ,boost::bidirectional_traversal_tag,unsigned int const &,int>::operator++ (13E18E0h) 013E1392 jmp main+230h (13E1380h) vertex_count++; // forever loop end It's easy to see that iterator handle is cached in EBP and it never gets incremented despite of a call to iterator operator++() function. I've replaced Itarator implmentation with one deriving from std::iterator and the issue persisted, so this is not iterator_facade fault. This problem exists only on msvc 2008 SP1 x86 and amd64 release builds. Debug builds on msvc 2008 and debug/release builds on msvc 2010 and gcc 4.4 (linux) works fine. Furthermore the BOOST_FOREACH block must be repeaded exacly 10 times. If it's repeaded 9 times, it's all OK. I guess that due to BOOST_FOREACH use of template trickery (const auto_any), compiler assumes that iterator handle is constant and never reads its real value again. I would be very happy to hear that my code is wrong, correct it and move on with BOOST_FOREACH, which I'm very found of (as opposed to BOOST_FOREVER :). May be related to: http://stackoverflow.com/questions/1275852/why-does-boost-foreach-not-work-sometimes-with-c-strings

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  • ASP.NET MVC 2 / Localization / Dynamic Default Value?

    - by cyberblast
    Hello In an ASP.NET MVC 2 application, i'm having a route like this: routes.MapRoute( "Default", // Route name "{lang}/{controller}/{action}/{id}", // URL with parameters new // Parameter defaults { controller = "Home", action = "Index", lang = "de", id = UrlParameter.Optional }, new { lang = new AllowedValuesRouteConstraint(new string[] { "de", "en", "fr", "it" }, StringComparison.InvariantCultureIgnoreCase) } Now, basically I would like to set the thread's culture according the language passed in. But there is one exception: If the user requests the page for the first time, like calling "http://www.mysite.com" I want to set the initial language if possible to the one "preferred by the browser". How can I distinguish in an early procesing stage (like global.asax), if the default parameter has been set because of the default value or mentioned explicit through the URL? (I would prefer a solution where the request URL is not getting parsed). Is there a way to dynamically provide a default-value for a paramter? Something like a hook? Or where can I override the default value (good application event?). This is the code i'm actually experimenting with: protected void Application_AcquireRequestState(object sender, EventArgs e) { string activeLanguage; string[] validLanguages; string defaultLanguage; string browsersPreferredLanguage; try { HttpContextBase contextBase = new HttpContextWrapper(Context); RouteData activeRoute = RouteTable.Routes.GetRouteData(new HttpContextWrapper(Context)); if (activeRoute == null) { return; } activeLanguage = activeRoute.GetRequiredString("lang"); Route route = (Route)activeRoute.Route; validLanguages = ((AllowedValuesRouteConstraint)route.Constraints["lang"]).AllowedValues; defaultLanguage = route.Defaults["lang"].ToString(); browsersPreferredLanguage = GetBrowsersPreferredLanguage(); //TODO: Better way than parsing the url bool defaultInitialized = contextBase.Request.Url.ToString().IndexOf(string.Format("/{0}/", defaultLanguage), StringComparison.InvariantCultureIgnoreCase) > -1; string languageToActivate = defaultLanguage; if (!defaultInitialized) { if (validLanguages.Contains(browsersPreferredLanguage, StringComparer.InvariantCultureIgnoreCase)) { languageToActivate = browsersPreferredLanguage; } } //TODO: Where and how to overwrtie the default value that it gets passed to the controller? contextBase.RewritePath(contextBase.Request.Path.Replace("/de/", "/en/")); SetLanguage(languageToActivate); } catch (Exception ex) { //TODO: Log Console.WriteLine(ex.Message); } } protected string GetBrowsersPreferredLanguage() { string acceptedLang = string.Empty; if (HttpContext.Current.Request.UserLanguages != null && HttpContext.Current.Request.UserLanguages.Length > 0) { acceptedLang = HttpContext.Current.Request.UserLanguages[0].Substring(0, 2); } return acceptedLang; } protected void SetLanguage(string languageToActivate) { CultureInfo cultureInfo = new CultureInfo(languageToActivate); if (!Thread.CurrentThread.CurrentUICulture.TwoLetterISOLanguageName.Equals(languageToActivate, StringComparison.InvariantCultureIgnoreCase)) { Thread.CurrentThread.CurrentUICulture = cultureInfo; } if (!Thread.CurrentThread.CurrentCulture.TwoLetterISOLanguageName.Equals(languageToActivate, StringComparison.InvariantCultureIgnoreCase)) { Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(cultureInfo.Name); } } The RouteConstraint to reproduce the sample: public class AllowedValuesRouteConstraint : IRouteConstraint { private string[] _allowedValues; private StringComparison _stringComparism; public string[] AllowedValues { get { return _allowedValues; } } public AllowedValuesRouteConstraint(string[] allowedValues, StringComparison stringComparism) { _allowedValues = allowedValues; _stringComparism = stringComparism; } public AllowedValuesRouteConstraint(string[] allowedValues) { _allowedValues = allowedValues; _stringComparism = StringComparison.InvariantCultureIgnoreCase; } public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) { if (_allowedValues != null) { return _allowedValues.Any(a => a.Equals(values[parameterName].ToString(), _stringComparism)); } else { return false; } } } Can someone help me out with that problem? Thanks, Martin

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  • Using undefined type.

    - by Knowing me knowing you
    //file list.h #include "stdafx.h" namespace st { struct My_List; typedef My_List list; list* create(const char* name); } //file list.cpp #include "stdafx.h" #include "list.h" namespace st { struct My_List { const char* name_; My_List* left_; My_List* right_; My_List(const char* name):name_(name), left_(nullptr), right_(nullptr) {} My_List(const My_List&); ~My_List() { } void insert(My_List*); void set_name(char* name) { name_ = name; } const char* get_name()const { return name_; } }; typedef My_List list; /*helper class for optor+ */ struct MyChar { const char* my_data_; MyChar(const char* c_string):my_data_(c_string){} operator const char*() { return my_data_; } operator char*() { return const_cast<char*>(my_data_); } }; char* operator+(MyChar left_, MyChar right_) { if (!left_.my_data_ || !right_.my_data_) { return 0; } size_t size = 1;//size is set to one for final '\0' char in an array char* p = "";//if both c_strings are empty this is returned bool has_left_ = false; bool has_right_ = false; if (strlen(left_)) { size += strlen(left_); has_left_ = true; } if (strlen(right_)) { size += strlen(right_); has_right_ = true; } bool both = has_left_ && has_right_ ? true : false; if (both) { p = new char[size](); const void* p_v = p;//just to keep address of beginning of p const char* tmp = left_; /*copying first c_string*/ while (*p++ = *tmp++); tmp = right_; /*one too far after last loop*/ --p; while (*p++ = *tmp++); *p = '\0'; /*go back to the beginning of an array*/ p = static_cast<char*>(const_cast<void*>(p_v)); return p; } else if (has_left_) { return left_; } else if (has_right_) { return right_; } return p;//returns "" if both c_strings were empty } My_List::My_List(const My_List& pat):left_(nullptr),right_(nullptr) { name_ = pat.name_ + MyChar("_cpy"); My_List* pattern = const_cast<My_List*>(&pat); My_List* target = this; while (pattern->right_) { target->right_ = static_cast<My_List*>(malloc(sizeof(My_List))); *target->right_ = *pattern->right_; target->right_->set_name(pattern->right_->get_name() + MyChar("_cpy")); target->right_->left_ = static_cast<My_List*>(malloc(sizeof(My_List))); *target->right_->left_ = *pattern->right_->left_; target->right_->left_->set_name(pattern->right_->left_->get_name() + MyChar("_cpy")); pattern = pattern->right_; target = target->right_; } } void My_List::insert(My_List* obj) { /*to catch first branch*/ My_List* tmp = this; if (tmp->right_) { /*go to the end of right side*/ while (tmp->right_) { tmp = tmp->right_; } tmp->right_ = obj; obj->left_ = tmp; } else { tmp->right_ = obj; obj->left_= this; } } My_List* create(const char* name) { return new My_List(name); } } //file main.cpp #include "stdafx.h" #include "list.h" using namespace st; int _tmain(int argc, _TCHAR* argv[]) { list* my = create("a"); list* b = create("b"); my->insert(b);//HERE I'M GETTING ERROR return 0; } err msg: 'Error 1 error C2027: use of undefined type 'st::My_List' 13' Why? Especially that if I comment this line it will get compiled and create() is using this type.

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  • Grafting LINQ onto C# 2 library

    - by P Daddy
    I'm writing a data access layer. It will have C# 2 and C# 3 clients, so I'm compiling against the 2.0 framework. Although encouraging the use of stored procedures, I'm still trying to provide a fairly complete ability to perform ad-hoc queries. I have this working fairly well, already. For the convenience of C# 3 clients, I'm trying to provide as much compatibility with LINQ query syntax as I can. Jon Skeet noticed that LINQ query expressions are duck typed, so I don't have to have an IQueryable and IQueryProvider (or IEnumerable<T>) to use them. I just have to provide methods with the correct signatures. So I got Select, Where, OrderBy, OrderByDescending, ThenBy, and ThenByDescending working. Where I need help are with Join and GroupJoin. I've got them working, but only for one join. A brief compilable example of what I have is this: // .NET 2.0 doesn't define the Func<...> delegates, so let's define some workalikes delegate TResult FakeFunc<T, TResult>(T arg); delegate TResult FakeFunc<T1, T2, TResult>(T1 arg1, T2 arg2); abstract class Projection{ public static Condition operator==(Projection a, Projection b){ return new EqualsCondition(a, b); } public static Condition operator!=(Projection a, Projection b){ throw new NotImplementedException(); } } class ColumnProjection : Projection{ readonly Table table; readonly string columnName; public ColumnProjection(Table table, string columnName){ this.table = table; this.columnName = columnName; } } abstract class Condition{} class EqualsCondition : Condition{ readonly Projection a; readonly Projection b; public EqualsCondition(Projection a, Projection b){ this.a = a; this.b = b; } } class TableView{ readonly Table table; readonly Projection[] projections; public TableView(Table table, Projection[] projections){ this.table = table; this.projections = projections; } } class Table{ public Projection this[string columnName]{ get{return new ColumnProjection(this, columnName);} } public TableView Select(params Projection[] projections){ return new TableView(this, projections); } public TableView Select(FakeFunc<Table, Projection[]> projections){ return new TableView(this, projections(this)); } public Table Join(Table other, Condition condition){ return new JoinedTable(this, other, condition); } public TableView Join(Table inner, FakeFunc<Table, Projection> outerKeySelector, FakeFunc<Table, Projection> innerKeySelector, FakeFunc<Table, Table, Projection[]> resultSelector){ Table join = new JoinedTable(this, inner, new EqualsCondition(outerKeySelector(this), innerKeySelector(inner))); return join.Select(resultSelector(this, inner)); } } class JoinedTable : Table{ readonly Table left; readonly Table right; readonly Condition condition; public JoinedTable(Table left, Table right, Condition condition){ this.left = left; this.right = right; this.condition = condition; } } This allows me to use a fairly decent syntax in C# 2: Table table1 = new Table(); Table table2 = new Table(); TableView result = table1 .Join(table2, table1["ID"] == table2["ID"]) .Select(table1["ID"], table2["Description"]); But an even nicer syntax in C# 3: TableView result = from t1 in table1 join t2 in table2 on t1["ID"] equals t2["ID"] select new[]{t1["ID"], t2["Description"]}; This works well and gives me identical results to the first case. The problem is if I want to join in a third table. TableView result = from t1 in table1 join t2 in table2 on t1["ID"] equals t2["ID"] join t3 in table3 on t1["ID"] equals t3["ID"] select new[]{t1["ID"], t2["Description"], t3["Foo"]}; Now I get an error (Cannot implicitly convert type 'AnonymousType#1' to 'Projection[]'), presumably because the second join is trying to join the third table to an anonymous type containing the first two tables. This anonymous type, of course, doesn't have a Join method. Any hints on how I can do this?

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  • Unable to start ServiceIntent android

    - by Mj1992
    I don't know why my service class is not working although it was working fine before. I've the following service class. public class MyIntentService extends IntentService { private static PowerManager.WakeLock sWakeLock; private static final Object LOCK = MyIntentService.class; public MyIntentService() { super("MuazzamService"); } @Override protected void onHandleIntent(Intent intent) { try { String action = intent.getAction(); <-- breakpoint if (action.equals("com.google.android.c2dm.intent.REGISTRATION")) <-- passes by { handleRegistration(intent); } else if (action.equals("com.google.android.c2dm.intent.RECEIVE")) { handleMessage(intent); } } finally { synchronized(LOCK) { sWakeLock.release(); } } } private void handleRegistration(Intent intent) { try { String registrationId = intent.getStringExtra("registration_id"); String error = intent.getStringExtra("error"); String unregistered = intent.getStringExtra("unregistered"); if (registrationId != null) { this.SendRegistrationIDViaHttp(registrationId); Log.i("Regid",registrationId); } if (unregistered != null) {} if (error != null) { if ("SERVICE_NOT_AVAILABLE".equals(error)) { Log.e("ServiceNoAvail",error); } else { Log.i("Error In Recieveing regid", "Received error: " + error); } } } catch(Exception e) { Log.e("ErrorHai(MIS0)",e.toString()); e.printStackTrace(); } } private void SendRegistrationIDViaHttp(String regID) { HttpClient httpclient = new DefaultHttpClient(); try { HttpGet httpget = new HttpGet("http://10.116.27.107/php/GCM/AndroidRequest.php?registrationID="+regID+"&[email protected]"); //test purposes k liye muazzam HttpResponse response = httpclient.execute(httpget); HttpEntity entity=response.getEntity(); if(entity!=null) { InputStream inputStream=entity.getContent(); String result= convertStreamToString(inputStream); Log.i("finalAnswer",result); // Toast.makeText(getApplicationContext(),regID, Toast.LENGTH_LONG).show(); } } catch (ClientProtocolException e) { Log.e("errorhai",e.getMessage()); e.printStackTrace(); } catch (IOException e) { Log.e("errorhai",e.getMessage()); e.printStackTrace(); } } private static String convertStreamToString(InputStream is) { BufferedReader reader = new BufferedReader(new InputStreamReader(is)); StringBuilder sb = new StringBuilder(); String line = null; try { while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } } catch (IOException e) { Log.e("ErrorHai(MIS)",e.toString()); e.printStackTrace(); } finally { try { is.close(); } catch (IOException e) { Log.e("ErrorHai(MIS2)",e.toString()); e.printStackTrace(); } } return sb.toString(); } private void handleMessage(Intent intent) { try { String score = intent.getStringExtra("score"); String time = intent.getStringExtra("time"); Toast.makeText(getApplicationContext(), "hjhhjjhjhjh", Toast.LENGTH_LONG).show(); Log.e("GetExtraScore",score.toString()); Log.e("GetExtratime",time.toString()); } catch(NullPointerException e) { Log.e("je bat",e.getMessage()); } } static void runIntentInService(Context context,Intent intent){ synchronized(LOCK) { if (sWakeLock == null) { PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE); sWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "my_wakelock"); } } sWakeLock.acquire(); intent.setClassName(context, MyIntentService.class.getName()); context.startService(intent); } } and here's how I am calling the service as mentioned in the android docs. Intent registrationIntent = new Intent("com.google.android.c2dm.intent.REGISTER"); registrationIntent.putExtra("app", PendingIntent.getBroadcast(this, 0, new Intent(), 0)); registrationIntent.putExtra("sender",Sender_ID); startService(registrationIntent); I've declared the service in the manifest file inside the application tag. <service android:name="com.pack.gcm.MyIntentService" android:enabled="true"/> I placed a breakpoint in my IntentService class but it never goes there.But if I declare my registrationIntent like this Intent registrationIntent = new Intent(getApplicationContext(),com.pack.gcm.MyIntentService); It works and goes to the breakpoint I've placed but intent.getAction() contains null and hence it doesn't go into the if condition placed after those lines. It says 07-08 02:10:03.755: W/ActivityManager(60): Unable to start service Intent { act=com.google.android.c2dm.intent.REGISTER (has extras) }: not found in the logcat.

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  • Template problems: No matching function for call

    - by Nick Sweet
    I'm trying to create a template class, and when I define a non-member template function, I get the "No matching function for call to randvec()" error. I have a template class defined as: template <class T> class Vector { T x, y, z; public: //constructors Vector(); Vector(const T& x, const T& y, const T& z); Vector(const Vector& u); //accessors T getx() const; T gety() const; T getz() const; //mutators void setx(const T& x); void sety(const T& y); void setz(const T& z); //operations void operator-(); Vector plus(const Vector& v); Vector minus(const Vector& v); Vector cross(const Vector& v); T dot(const Vector& v); void times(const T& s); T length() const; //Vector<T>& randvec(); //operators Vector& operator=(const Vector& rhs); friend std::ostream& operator<< <T>(std::ostream&, const Vector<T>&); }; and the function in question, which I've defined after all those functions above, is: //random Vector template <class T> Vector<double>& randvec() { const int min=-10, max=10; Vector<double>* r = new Vector<double>; int randx, randy, randz, temp; const int bucket_size = RAND_MAX/(max-min +1); temp = rand(); //voodoo hackery do randx = (rand()/bucket_size)+min; while (randx < min || randx > max); r->setx(randx); do randy = (rand()/bucket_size)+min; while (randy < min || randy > max); r->sety(randy); do randz = (rand()/bucket_size)+min; while (randz < min || randz > max); r->setz(randz); return *r; } Yet, every time I call it in my main function using a line like: Vector<double> a(randvec()); I get that error. However, if I remove the template and define it using 'double' instead of 'T', the call to randvec() works perfectly. Why doesn't it recognize randvec()? P.S. Don't mind the bit labeled voodoo hackery - this is just a cheap hack so that I can get around another problem I encountered.

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  • My IDE is showing "undeclared FileNotFoundException must be caught or thrown"

    - by Dan Czarnecki
    I am having the following issue above. I have tried actually putting a try-catch statement into the code as you will see below, but I can't get the compiler to get past that. import java.io.*; public class DirectoryStatistics extends DirectorySize { /* Dan Czarnecki October 24, 2013 Class variables: private File directory A File object that holds the pathname of the directory to look in private long sizeInBytes A variable of type long that holds the size of a file/directory (in bytes) private long fileCount A variable of type long that holds the number of files in a directory Constructors: public DirectoryStatistics(File startingDirectory) throws FileNotFoundException Creates a DirectoryStatistics object, given a pathname (inherited from DirectorySize class), and has 3 instance variables that hold the directory to search in, the size of each file (in bytes), and the number of files within the directory Modification history: October 24, 2013 Original version of class */ private File directory; private long sizeInBytes; private long fileCount; public DirectoryStatistics(File startingDirectory) throws FileNotFoundException { super(startingDirectory); try { if(directory == null) { throw new IllegalArgumentException("null input"); } if(directory.isDirectory() == false) { throw new FileNotFoundException("the following input is not a directory!"); } } catch(IOException ioe) { System.out.println("You have not entered a directory. Please try again."); } } public File getDirectory() { return this.directory; } public long getSizeInBytes() { return this.sizeInBytes; } public long getFileCount() { return this.fileCount; } public long setFileCount(long size) { fileCount = size; return size; } public long setSizeInBytes(long size) { sizeInBytes = size; return size; } public void incrementFileCount() { fileCount = fileCount + 1; } public void addToSizeInBytes(long addend) { sizeInBytes = sizeInBytes + addend; } public String toString() { return "Directory" + this.directory + "Size (in bytes) " + this.sizeInBytes + "Number of files: " + this.fileCount; } public int hashCode() { return this.directory.hashCode(); } public boolean equals(DirectoryStatistics other) { return this.equals(other); } } import java.io.*; import java.util.*; public class DirectorySize extends DirectoryProcessor { /* Dan Czarnecki October 17, 2013 Class variables: private Vector<Long> directorySizeList Variable of type Vector<Long> that holds the total file size of files in that directory as well as files within folders of that directory private Vector<File> currentFile Variable of type Vector<File> that holds the parent directory Constructors: public DirectorySize(File startingDirectory) throws FileNotFoundException Creates a DirectorySize object, takes in a pathname (inherited from DirectoryProcessor class, and has a single vector of a DirectoryStatistics object to hold the files and folders within a directory Modification History October 17, 2013 Original version of class Implemented run() and processFile() methods */ private Vector<DirectoryStatistics> directory; /* private Vector<Long> directorySizeList; private Vector<File> currentFile; */ public DirectorySize(File startingDirectory) throws FileNotFoundException { super(startingDirectory); directory = new Vector<DirectoryStatistics>(); } public void processFile(File file) { DirectoryStatistics parent; int index; File parentFile; System.out.println(file.getName()); System.out.println(file.getParent()); parentFile = file.getParentFile(); parent = new DirectoryStatistics(parentFile); System.out.println(parent); parent.equals(parent); index = directory.indexOf(parent); if(index == 0) { directory.elementAt(index).addToSizeInBytes(file.length()); directory.elementAt(index).incrementFileCount(); } if(index < 0) { directory.addElement(parent); directory.lastElement().setSizeInBytes(file.length()); directory.lastElement().incrementFileCount(); } Could someone tell me why I'm getting this issue?

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  • Foreign key not stored in child entity (one-to-many)

    - by Kamil Los
    Hi, I'm quite new to hibernate and have stumbled on this problem, which I can't find solution for. When persisting parent object (with one-to-many relationship with child), the foreign-key to this parent is not stored in child's table. My classes: Parent.java @javax.persistence.Table(name = "PARENT") @Entity public class PARENT { private Integer id; @javax.persistence.Column(name = "ID") @Id @GeneratedValue(strategy=GenerationType.AUTO) public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } private Collection<Child> children; @OneToMany(mappedBy = "parent", fetch = FetchType.EAGER, cascade = {CascadeType.ALL}) @Cascade({org.hibernate.annotations.CascadeType.ALL}) public Collection<Child> getChildren() { return children; } public void setChildren(Collection<Child> children) { this.children = children; } } Child.java @javax.persistence.Table(name = "CHILD") @Entity @IdClass(Child.ChildId.class) public class Child { private String childId1; @Id public String getChildId1() { return childId1; } public void setChildId1(String childId1) { this.childId1 = childId1; } private String childId2; @Id public String getChildId2() { return childId2; } public void setChildId2(String childId2) { this.childId2 = childId2; } private Parent parent; @ManyToOne @javax.persistence.JoinColumn(name = "PARENT_ID", referencedColumnName = "ID") public Parent getParent() { return parent; } public void setParent(Operation parent) { this.parent = parent; } public static class ChildId implements Serializable { private String childId1; @javax.persistence.Column(name = "CHILD_ID1") public String getChildId1() { return childId1; } public void setChildId1(String childId1) { this.childId1 = childId1; } private String childId2; @javax.persistence.Column(name = "CHIILD_ID2") public String getChildId2() { return childId2; } public void setChildId2(String childId2) { this.childId2 = childId2; } public ChildId() { } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ChildId that = (ChildId) o; if (childId1 != null ? !childId1.equals(that.childId1) : that.childId1 != null) return false; if (childId2 != null ? !childId2.equals(that.childId2) : that.childId2 != null) return false; return true; } @Override public int hashCode() { int result = childId1 != null ? childId1.hashCode() : 0; result = 31 * result + (childId2 != null ? childId2.hashCode() : 0); return result; } } } Test.java public class Test() { private ParentDao parentDao; public void setParentDao(ParentDao parentDao) { this.parentDao = parentDao; } private ChildDao childDao; public void setChildDao(ChildDao childDao) { this.childDao = parentDao; } test1() { Parent parent = new Parent(); Child child = new Child(); child.setChildId1("a"); child.setChildId2("b"); ArrayList<Child> children = new ArrayList<Child>(); children.add(child); parent.setChildren(children); parent.setValue("value"); parentDao.save(parent); //calls hibernate's currentSession.saveOrUpdate(entity) } test2() { Parent parent = new Parent(); parent.setValue("value"); parentDao.save(parent); //calls hibernate's currentSession.saveOrUpdate(entity) Child child = new Child(); child.setChildId1("a"); child.setChildId2("b"); child.setParent(parent); childDao.save(); //calls hibernate's currentSession.saveOrUpdate(entity) } } When calling test1(), both entities get written to database, but field PARENT_ID in CHILD table stays empty. The only workaround I have so far is test2() - persisting parent first, and then the child. My goal is to persist parent and its children in one call to save() on Parent. Any ideas?

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  • Java: How to check the random letters from a-z, out of 10 letters minimum 2 letter should be a vowel

    - by kalandar
    I am writing a program to validate the following scenarios: Scenario 1: I am using the Random class from java.util. The random class will generate 10 letters from a-z and within 10 letter, minimum 2 letters must be a vowels. Scenario 2: When the player 1 and player 2 form a word from A-Z, he will score some points. There will be a score for each letter. I have already assigned the values for A-Z. At the end of the game, the system should display a scores for player 1 and player 2. How do i do it? Please help. I will post my code here. Thanks a lot. =========================================== import java.util.Random; import java.util.Scanner; public class FindYourWords { public static void main(String[] args) { Random rand = new Random(); Scanner userInput = new Scanner(System.in); //==================Player object=============================================== Player playerOne = new Player(); playerOne.wordScore = 0; playerOne.choice = "blah"; playerOne.turn = true; Player playerTwo = new Player(); playerTwo.wordScore = 0; playerTwo.choice = "blah"; playerTwo.turn = false; //================== Alphabet ================================================== String[] newChars = { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" }; //values of the 26 alphabets to be used int [] letterScore = {1,3,3,2,1,4,2,4,1,8,5,1,3,1,1,3,10,1,1,1,1,4,4,8,4,10}; // to assign score to the player1 and player 2 String[] vowel = { "a", "e", "i", "o", "u" }; // values for vowels int vow=0; System.out.println("FINDYOURWORDS\n"); int[] arrayRandom = new int[10]; //int array for word limiter String[] randomLetter = new String[10]; //storing the letters in newChars into this array //=============================================================================== boolean cont = true; while (cont) { if (playerOne.turn) { System.out.print("Letters of Player 1: "); } else if (!playerOne.turn) { System.out.print("Letters of Player 2: "); } for (int i = 0; i < arrayRandom.length; i++) { //running through the array limiter int r = rand.nextInt(newChars.length); //assigning random nums to the array of letters randomLetter[i] = newChars[r]; System.out.print(randomLetter[i]+ " "); } //input section for player System.out.println(""); System.out.println("Enter your word (or '@' to pass or '!' to quit): "); if (playerOne.turn) { playerOne.choice = userInput.next(); System.out.println(playerOne.turn); playerOne.turn = false; } else if (!playerOne.turn){ playerTwo.choice = userInput.next(); System.out.println(playerOne.turn); playerOne.turn = true; } //System.out.println(choice); String[] wordList = FileUtil.readDictFromFile("words.txt"); //Still dunno what this is for if (playerOne.choice.equals("@")) { playerOne.turn = false; } else if (playerTwo.choice.equals("@")) { playerOne.turn = true; } else if (playerOne.choice.equals("!")) { cont = false; } for (int i = 0; i < wordList.length; i++) { //System.out.println(wordList[i]); if (playerOne.choice.equalsIgnoreCase(wordList[i]) || playerTwo.choice.equalsIgnoreCase(wordList[i])){ } } } }}

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  • Reconciling a new BindingList into a master BindingList using LINQ

    - by Neo
    I have a seemingly simple problem whereby I wish to reconcile two lists so that an 'old' master list is updated by a 'new' list containing updated elements. Elements are denoted by a key property. These are my requirements: All elements in either list that have the same key results in an assignment of that element from the 'new' list over the original element in the 'old' list only if any properties have changed. Any elements in the 'new' list that have keys not in the 'old' list will be added to the 'old' list. Any elements in the 'old' list that have keys not in the 'new' list will be removed from the 'old' list. I found an equivalent problem here - http://stackoverflow.com/questions/161432/ - but it hasn't really been answered properly. So, I came up with an algorithm to iterate through the old and new lists and perform the reconciliation as per the above. Before anyone asks why I'm not just replacing the old list object with the new list object in its entirety, it's for presentation purposes - this is a BindingList bound to a grid on a GUI and I need to prevent refresh artifacts such as blinking, scrollbars moving, etc. So the list object must remain the same, only its updated elements changed. Another thing to note is that the objects in the 'new' list, even if the key is the same and all the properties are the same, are completely different instances to the equivalent objects in the 'old' list, so copying references is not an option. Below is what I've come up with so far - it's a generic extension method for a BindingList. I've put comments in to demonstrate what I'm trying to do. public static class BindingListExtension { public static void Reconcile<T>(this BindingList<T> left, BindingList<T> right, string key) { PropertyInfo piKey = typeof(T).GetProperty(key); // Go through each item in the new list in order to find all updated and new elements foreach (T newObj in right) { // First, find an object in the new list that shares its key with an object in the old list T oldObj = left.First(call => piKey.GetValue(call, null).Equals(piKey.GetValue(newObj, null))); if (oldObj != null) { // An object in each list was found with the same key, so now check to see if any properties have changed and // if any have, then assign the object from the new list over the top of the equivalent element in the old list foreach (PropertyInfo pi in typeof(T).GetProperties()) { if (!pi.GetValue(oldObj, null).Equals(pi.GetValue(newObj, null))) { left[left.IndexOf(oldObj)] = newObj; break; } } } else { // The object in the new list is brand new (has a new key), so add it to the old list left.Add(newObj); } } // Now, go through each item in the old list to find all elements with keys no longer in the new list foreach (T oldObj in left) { // Look for an element in the new list with a key matching an element in the old list if (right.First(call => piKey.GetValue(call, null).Equals(piKey.GetValue(oldObj, null))) == null) { // A matching element cannot be found in the new list, so remove the item from the old list left.Remove(oldObj); } } } } It can be called like this: _oldBindingList.Reconcile(newBindingList, "MyKey") However, I'm looking for perhaps a method of doing the same using LINQ type methods such as GroupJoin<, Join<, Select<, SelectMany<, Intersect<, etc. So far, the problem I've had is that each of these LINQ type methods result in brand new intermediary lists (as a return value) and really, I only want to modify the existing list for all the above reasons. If anyone can help with this, would be most appreciated. If not, no worries, the above method (as it were) will suffice for now. Thanks, Jason

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  • Do classes which have a vector has a member have memory issues

    - by user263766
    I am just starting out C++, so sorry if this is a dumb question. I have a class Braid whose members are vectors. I have not written an assignment operator. When I do a lot of assignments to an object of the type Braid, I run into memory issues :- 0 0xb7daff89 in _int_malloc () from /lib/libc.so.6 #1 0xb7db2583 in malloc () from /lib/libc.so.6 #2 0xb7f8ac59 in operator new(unsigned int) () from /usr/lib/libstdc++.so.6 #3 0x0804d05e in __gnu_cxx::new_allocator<int>::allocate (this=0xbf800204, __n=1) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/ext/new_allocator.h:89 #4 0x0804cb0e in std::_Vector_base<int, std::allocator<int> >::_M_allocate (this=0xbf800204, __n=1) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:140 #5 0x0804c086 in _Vector_base (this=0xbf800204, __n=1, __a=...) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:113 #6 0x0804b4b7 in vector (this=0xbf800204, __x=...) at /usr/lib/gcc/i686-pc-linux-gnu/4.4.3/../../../../include/c++/4.4.3/bits/stl_vector.h:242 #7 0x0804b234 in Braid (this=0xbf800204) at braid.h:13 #8 0x080495ed in Braid::cycleBraid (this=0xbf8001b4) at braid.cpp:191 #9 0x080497c6 in Braid::score (this=0xbf800298, b=...) at braid.cpp:251 #10 0x08049c46 in Braid::evaluateMove (this=0xbf800468, move=1, pos=0, depth=2, b=...) I suspect that these memory issues are because the vectors are getting resized. What I want to know is whether objects of type Braid automatically expand when its members expand? he code I am writing is really long so I will post the section which is causing the problems. Here is the relevant section of the code :- class Braid { private : vector<int> braid; //Stores the braid. int strands; vector < vector<bool> > history; vector < vector<bool> > CM; public : Braid () : strands(0) {} Braid operator * (Braid); Braid* inputBraid(int,vector<int>); int printBraid(); int printBraid(vector<vector<int>::iterator>); vector<int>::size_type size() const; ..... ..... } Here is the function which causes the issue :- int Braid::evaluateMove(int move,int pos,int depth,Braid b) { int netscore = 0; Braid curr(*this); curr = curr.move(move,pos); netscore += curr.score(b); while(depth > 1) { netscore += curr.evaluateMove(1,0,depth,b); netscore += curr.evaluateMove(2,0,depth,b); for(int i = 0; i < braid.size();++i) { netscore += curr.evaluateMove(3,i,depth,b); netscore += curr.evaluateMove(4,i,depth,b); netscore += curr.evaluateMove(5,i,depth,b); curr = curr.cycleBraid(); netscore += curr.evaluateMove(6,0,depth,b); } --depth; } return netscore; }

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  • compareTo() method java is acting weird

    - by Ron Paul
    hi im having trouble getting this to work im getting an error here with my object comparison...how could I cast the inches to a string ( i never used compare to with anything other than strings) , or use comparison operators to compare the intigers, Object comparison = this.inches.compareTo(obj.inches); here is my code so far import java.io.*; import java.util.*; import java.lang.Integer; import java.lang.reflect.Array; public class Distance implements Comparable<Distance> { private static final String HashCodeUtil = null; private int feet; private int inches; private final int DEFAULT_FT = 1; private final int DEFAULT_IN = 1; public Distance(){ feet = DEFAULT_FT; inches = DEFAULT_IN; } public Distance(int ft, int in){ feet = ft; inches = in; } public void setFeet(int ft){ try { if(ft<0){ throw new CustomException("Distance is not negative"); } } catch(CustomException c){ System.err.println(c); feet =ft; } } public int getFeet(){ return feet; } public void setInches(int in){ try { if (in<0) throw new CustomException("Distance is not negative"); //inches = in; } catch(CustomException c) { System.err.println(c); inches = in; } } public int getInches(){ return inches; } public String toString (){ return "<" + feet + ":" + inches + ">"; } public Distance add(Distance m){ Distance n = new Distance(); n.inches = this.inches + m.inches; n.feet = this.feet + m.feet; while(n.inches>12){ n.inches = n.inches - 12; n.feet++; } return n; } public Distance subtract(Distance f){ Distance m = new Distance(); m.inches = this.inches - f.inches; m.feet = this.feet - f.feet; while(m.inches<0){ m.inches = m.inches - 12; feet--; } return m; } @Override public int compareTo(Distance obj) { // TODO Auto-generated method stub final int BEFORE = -1; final int EQUAL = 0; final int AFTER = 1; if (this == obj) return EQUAL; if(this.DEFAULT_IN < obj.DEFAULT_FT) return BEFORE; if(this.DEFAULT_IN > obj.DEFAULT_FT) return AFTER; Object comparison = this.inches.compareTo(obj.inches); if (this.inches == obj.inches) return compareTo(null); assert this.equals(obj) : "compareTo inconsistent with equals"; return EQUAL; } @Override public boolean equals( Object obj){ if (obj != null) return false; if (!(obj intanceof Distance)) return false; Distance that = (Distance)obj; ( this.feet == that.feet && this.inches == that.inches); return true; else return false; } @Override public int hashCode(int, int) { int result = HashCodeUtil.inches; result = HashCodeUtil.hash(result, inches ); result = HashCodeUtil.hash(result, feet); ruturn result; }

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  • concurrency::accelerator_view

    - by Daniel Moth
    Overview We saw previously that accelerator represents a target for our C++ AMP computation or memory allocation and that there is a notion of a default accelerator. We ended that post by introducing how one can obtain accelerator_view objects from an accelerator object through the accelerator class's default_view property and the create_view method. The accelerator_view objects can be thought of as handles to an accelerator. You can also construct an accelerator_view given another accelerator_view (through the copy constructor or the assignment operator overload). Speaking of operator overloading, you can also compare (for equality and inequality) two accelerator_view objects between them to determine if they refer to the same underlying accelerator. We'll see later that when we use concurrency::array objects, the allocation of data takes place on an accelerator at array construction time, so there is a constructor overload that accepts an accelerator_view object. We'll also see later that a new concurrency::parallel_for_each function overload can take an accelerator_view object, so it knows on what target to execute the computation (represented by a lambda that the parallel_for_each also accepts). Beyond normal usage, accelerator_view is a quality of service concept that offers isolation to multiple "consumers" of an accelerator. If in your code you are accessing the accelerator from multiple threads (or, in general, from different parts of your app), then you'll want to create separate accelerator_view objects for each thread. flush, wait, and queuing_mode When you create an accelerator_view via the create_view method of the accelerator, you pass in an option of immediate or deferred, which are the two members of the queuing_mode enum. At any point you can access this value from the queuing_mode property of the accelerator_view. When the queuing_mode value is immediate (which is the default), any commands sent to the device such as kernel invocations and data transfers (e.g. parallel_for_each and copy, as we'll see in future posts), will get submitted as soon as the runtime sees fit (that is the definition of immediate). When the value of queuing_mode is deferred, the commands will be batched up. To send all buffered commands to the device for execution, there is a non-blocking flush method that you can call. If you wish to block until all the commands have been sent, there is a wait method you can call. Deferring is a more advanced scenario aimed at performance gains when you are submitting many device commands and you want to avoid the tiny overhead of flushing/submitting each command separately. Querying information Just like accelerator, accelerator_view exposes the is_debug and version properties. In fact, you can always access the accelerator object from the accelerator property on the accelerator_view class to access the accelerator interface we looked at previously. Interop with D3D (aka DX) In a later post I'll show an example of an app that uses C++ AMP to compute data that is used in pixel shaders. In those scenarios, you can benefit by integrating C++ AMP into your graphics pipeline and one of the building blocks for that is being able to use the same device context from both the compute kernel and the other shaders. You can do that by going from accelerator_view to device context (and vice versa), through part of our interop API in amp.h: *get_device, create_accelerator_view. More on those in a later post. Comments about this post by Daniel Moth welcome at the original blog.

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  • Silabs cp2102 driver problem

    - by Zxy
    I downloaded appropriate driver from its own site, unzipped it and then tried to install it. But: root@ghostrider:/home/zero/Downloads# tar xvf cp210x-3.1.0.tar.gz cp210x-3.1.0/ cp210x-3.1.0/COPYING cp210x-3.1.0/cp210x/ cp210x-3.1.0/cp210x-3.1.0.spec cp210x-3.1.0/cp210x/.rpmmacros cp210x-3.1.0/cp210x/configure cp210x-3.1.0/cp210x/cp210x.c cp210x-3.1.0/cp210x/cp210x.h cp210x-3.1.0/cp210x/cp210xuniversal.c cp210x-3.1.0/cp210x/cp210xuniversal.h cp210x-3.1.0/cp210x/installmod cp210x-3.1.0/cp210x/Makefile24 cp210x-3.1.0/cp210x/Makefile26 cp210x-3.1.0/cp210x/rpmmacros24 cp210x-3.1.0/cp210x/rpmmacros26 cp210x-3.1.0/cp210x/Rules.make cp210x-3.1.0/INSTALL cp210x-3.1.0/makerpm cp210x-3.1.0/PACKAGE-LIST cp210x-3.1.0/README cp210x-3.1.0/RELEASE-NOTES cp210x-3.1.0/REPORTING-BUGS cp210x-3.1.0/rpm/ cp210x-3.1.0/rpm/brp-java-repack-jars cp210x-3.1.0/rpm/brp-python-bytecompile cp210x-3.1.0/rpm/check-rpaths cp210x-3.1.0/rpm/check-rpaths-worker root@ghostrider:/home/zero/Downloads# cd cp210x-3.1.0 root@ghostrider:/home/zero/Downloads/cp210x-3.1.0# ls COPYING cp210x-3.1.0.spec makerpm README REPORTING-BUGS cp210x INSTALL PACKAGE-LIST RELEASE-NOTES rpm root@ghostrider:/home/zero/Downloads/cp210x-3.1.0# run ./makerpm No command 'run' found, did you mean: Command 'zrun' from package 'moreutils' (universe) Command 'runq' from package 'exim4-daemon-heavy' (main) Command 'runq' from package 'exim4-daemon-light' (main) Command 'runq' from package 'sendmail-bin' (universe) Command 'grun' from package 'grun' (universe) Command 'qrun' from package 'torque-client' (universe) Command 'qrun' from package 'torque-client-x11' (universe) Command 'lrun' from package 'lustre-utils' (universe) Command 'rn' from package 'trn' (multiverse) Command 'rn' from package 'trn4' (multiverse) Command 'rup' from package 'rstat-client' (universe) Command 'srun' from package 'slurm-llnl' (universe) run: command not found root@ghostrider:/home/zero/Downloads/cp210x-3.1.0# sudo ./makerpm + uname -r + kernel_release=3.2.0-25-generic-pae + pwd + current_dir=/home/zero/Downloads/cp210x-3.1.0 + export current_dir + uname -r + KVER=3.2.0-25-generic-pae + echo 3.2.0-25-generic-pae + awk -F . -- { print $1 } + KVER1=3 + echo 3.2.0-25-generic-pae + awk -F . -- { print $2 } + KVER2=2 + sed -e s/3\.2\.//g + echo 3.2.0-25-generic-pae + KVER3=0-25-generic-pae + [ -f /root/.rpmmacros ] + echo 2 2 + [ 2 == 4 ] ./makerpm: 25: [: 2: unexpected operator + echo 0-25-generic-pae 0-25-generic-pae + [ 0-25-generic-pae -gt 15 ] ./makerpm: 29: [: Illegal number: 0-25-generic-pae + cp /home/zero/Downloads/cp210x-3.1.0/cp210x/rpmmacros24 /root/.rpmmacros + d=/var/tmp/silabs + [ ! -d /var/tmp/silabs ] + mkdir /var/tmp/silabs + cd /var/tmp/silabs + r=/var/tmp/silabs/rpmbuild + o=cp210x-3.1.0 + s=/var/tmp/silabs/rpmbuild/SOURCES + spec=cp210x-3.1.0.spec + rm -rf /var/tmp/silabs/rpmbuild + mkdir rpmbuild + mkdir rpmbuild/SOURCES + mkdir rpmbuild/SRPMS + mkdir rpmbuild/SPECS + mkdir rpmbuild/BUILD + mkdir rpmbuild/RPMS + cd /var/tmp/silabs/rpmbuild/SOURCES + rm -rf cp210x-3.1.0 + mkdir cp210x-3.1.0 + cp -r /home/zero/Downloads/cp210x-3.1.0/cp210x/Makefile24 /home/zero/Downloads/cp210x-3.1.0/cp210x/Makefile26 /home/zero/Downloads/cp210x- 3.1.0/cp210x/Rules.make /home/zero/Downloads/cp210x-3.1.0/cp210x/configure /home/zero/Downloads/cp210x-3.1.0/cp210x/cp210x.c /home/zero/Downloads/cp210x- 3.1.0/cp210x/cp210x.h /home/zero/Downloads/cp210x-3.1.0/cp210x/cp210xuniversal.c /home/zero/Downloads/cp210x-3.1.0/cp210x/cp210xuniversal.h /home/zero/Downloads/cp210x- 3.1.0/cp210x/installmod /home/zero/Downloads/cp210x-3.1.0/cp210x/rpmmacros24 /home/zero/Downloads/cp210x-3.1.0/cp210x/rpmmacros26 cp210x-3.1.0 + echo 2 2 + [ 2 == 4 ] ./makerpm: 64: [: 2: unexpected operator + echo 0-25-generic-pae 0-25-generic-pae + [ 0-25-generic-pae -gt 15 ] ./makerpm: 68: [: Illegal number: 0-25-generic-pae + cp /home/zero/Downloads/cp210x-3.1.0/cp210x/.rpmmacros24 cp210x-3.1.0/.rpmmacros cp: cannot stat `/home/zero/Downloads/cp210x-3.1.0/cp210x/.rpmmacros24': No such file or directory + MyCopy=0 + rm -f cp210x-3.1.0.tar + rm -f cp210x-3.1.0.tar.gz + tar -cf cp210x-3.1.0.tar cp210x-3.1.0 + gzip cp210x-3.1.0.tar + cp /home/zero/Downloads/cp210x-3.1.0/cp210x-3.1.0.spec /var/tmp/silabs/rpmbuild/SPECS + rpmbuild -ba /var/tmp/silabs/rpmbuild/SPECS/cp210x-3.1.0.spec ./makerpm: 121: ./makerpm: rpmbuild: not found + [ -f /root/.rpmmacros.cp210x ] How may I solve my problem? Thanks

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  • Why you need to tag your build servers in TFS

    - by Martin Hinshelwood
    At SSW we use gated check-in for all of our projects. The benefits are based on the number of developers you have working on your project. Lets say you have 30 developers and each developer breaks the build once per month. That could mean that you have a broken build every day! Gated check-ins help, but they have a down side that manifests as queued builds and moaning developers. The way to combat this is to have more build servers, but with that comes complexity. Inevitably you will need to install components that you would expect to be installed on target computers, but how do you keep track of which build servers have which bits? What about a geographically diverse team? If you have a centrally controlled infrastructure you might have build servers in multiple regions and you don’t want teams in Sydney copying files from Beijing and vice a versa on a regular basis. So, what is the answer. Its Tags. You can add a set of Tags to your agents and then set which tags to look for in the build definition. Figure: Open up your Build Controller Manager Select “Build | Manage Build Controllers…” to get a list of all of your controllers and he build agents that are associated with them. Figure: the list of build agents and their controllers Each of these Agents might be subtly different. For example only one of these agents has FTP software installed. This software is required for only one of the many builds we have set up. My ethos for build servers is to keep them as clean as possible and not to install anything that is not absolutely necessary. For me that means anything that does not add a *.target file is suspect, and should really be under version control and called via the command line from there. So, some of the things you may install are: Silverlight 4 SDK Visual Studio 2010 Visual Studio 2008 WIX etc You should not install things that will not end up on the target users computer. For a website that means something different to a client than to a server, but I am sure you get the idea. One thing you can do to make things easier is to create a tag for each of the things that you install. that way developers can find the things they need. We may change to using a more generic tagging structure (Like “Web Application” or “WinForms Application”) if this gets too unwieldy, but for now the list of tags is limited. Figure: Tags associated with one of our build agents Once you have your Build Agents all tagged up ALL your builds will start to fail This is because the default setting for a build is to look for an Agent that exactly matches the tags for the build, and we have not added any yet. The quick way to fix this is to change the “Tag Comparison Operator” from “ExactMatch” to “MatchAtLease” to get your build immediately working. Figure: Tag Comparison Operator changes to MatchAtLeast to get builds to run. The next thing to do is look for specific tags. You just select from the list of available tags and the controller will make sure you get to a build agent that uses them. Figure: I want Silverlight, VS2010 and WIX, but do not care about Location. And there you go, you can now have build agents for different purposes and regions within the same environment. You can also use name filtering, so if you have a good Agent naming convention you can filter by that for regions. For example, your Agents might be “SYDVMAPTFSBP01” and “SYDVMAPTFSBP02” so a name filter of “SYD*” would target all of the Sydney build agents. Figure: Agent names can be used for filtering as well This flexibility will allow you to build better software by reducing the likelihood of not having a certain dependency on the target machines. Figure: Setting the name filter based on server location  Used in combination there is a lot of power here to coordinate tens of build servers for multiple projects across multiple regions so your developers get the most out of your environment. Technorati Tags: ALM,TFBS,TFS 2010,TFS Admin

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  • How should an object that uses composition set its composed components?

    - by Casey
    After struggling with various problems and reading up on component-based systems and reading Bob Nystrom's excellent book "Game Programming Patterns" and in particular the chapter on Components I determined that this is a horrible idea: //Class intended to be inherited by all objects. Engine uses Objects exclusively. class Object : public IUpdatable, public IDrawable { public: Object(); Object(const Object& other); Object& operator=(const Object& rhs); virtual ~Object() =0; virtual void SetBody(const RigidBodyDef& body); virtual const RigidBody* GetBody() const; virtual RigidBody* GetBody(); //Inherited from IUpdatable virtual void Update(double deltaTime); //Inherited from IDrawable virtual void Draw(BITMAP* dest); protected: private: }; I'm attempting to refactor it into a more manageable system. Mr. Nystrom uses the constructor to set the individual components; CHANGING these components at run-time is impossible. It's intended to be derived and be used in derivative classes or factory methods where their constructors do not change at run-time. i.e. his Bjorne object is just a call to a factory method with a specific call to the GameObject constructor. Is this a good idea? Should the object have a default constructor and setters to facilitate run-time changes or no default constructor without setters and instead use a factory method? Given: class Object { public: //...See below for constructor implementation concerns. Object(const Object& other); Object& operator=(const Object& rhs); virtual ~Object() =0; //See below for Setter concerns IUpdatable* GetUpdater(); IDrawable* GetRenderer(); protected: IUpdatable* _updater; IDrawable* _renderer; private: }; Should the components be read-only and passed in to the constructor via: class Object { public: //No default constructor. Object(IUpdatable* updater, IDrawable* renderer); //...remainder is same as above... }; or Should a default constructor be provided and then the components can be set at run-time? class Object { public: Object(); //... SetUpdater(IUpdater* updater); SetRenderer(IDrawable* renderer); //...remainder is same as above... }; or both? class Object { public: Object(); Object(IUpdater* updater, IDrawable* renderer); //... SetUpdater(IUpdater* updater); SetRenderer(IDrawable* renderer); //...remainder is same as above... };

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  • SQL SERVER – Puzzle #1 – Querying Pattern Ranges and Wild Cards

    - by Pinal Dave
    Note: Read at the end of the blog post how you can get five Joes 2 Pros Book #1 and a surprise gift. I have been blogging for almost 7 years and every other day I receive questions about Querying Pattern Ranges. The most common way to solve the problem is to use Wild Cards. However, not everyone knows how to use wild card properly. SQL Queries 2012 Joes 2 Pros Volume 1 – The SQL Queries 2012 Hands-On Tutorial for Beginners Book On Amazon | Book On Flipkart Learn SQL Server get all the five parts combo kit Kit on Amazon | Kit on Flipkart Many people know wildcards are great for finding patterns in character data. There are also some special sequences with wildcards that can give you even more power. This series from SQL Queries 2012 Joes 2 Pros® Volume 1 will show you some of these cool tricks. All supporting files are available with a free download from the www.Joes2Pros.com web site. This example is from the SQL 2012 series Volume 1 in the file SQLQueries2012Vol1Chapter2.2Setup.sql. If you need help setting up then look in the “Free Videos” section on Joes2Pros under “Getting Started” called “How to install your labs” Querying Pattern Ranges The % wildcard character represents any number of characters of any length. Let’s find all first names that end in the letter ‘A’. By using the percentage ‘%’ sign with the letter ‘A’, we achieve this goal using the code sample below: SELECT * FROM Employee WHERE FirstName LIKE '%A' To find all FirstName values beginning with the letters ‘A’ or ‘B’ we can use two predicates in our WHERE clause, by separating them with the OR statement. Finding names beginning with an ‘A’ or ‘B’ is easy and this works fine until we want a larger range of letters as in the example below for ‘A’ thru ‘K’: SELECT * FROM Employee WHERE FirstName LIKE 'A%' OR FirstName LIKE 'B%' OR FirstName LIKE 'C%' OR FirstName LIKE 'D%' OR FirstName LIKE 'E%' OR FirstName LIKE 'F%' OR FirstName LIKE 'G%' OR FirstName LIKE 'H%' OR FirstName LIKE 'I%' OR FirstName LIKE 'J%' OR FirstName LIKE 'K%' The previous query does find FirstName values beginning with the letters ‘A’ thru ‘K’. However, when a query requires a large range of letters, the LIKE operator has an even better option. Since the first letter of the FirstName field can be ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’ or ‘K’, simply list all these choices inside a set of square brackets followed by the ‘%’ wildcard, as in the example below: SELECT * FROM Employee WHERE FirstName LIKE '[ABCDEFGHIJK]%' A more elegant example of this technique recognizes that all these letters are in a continuous range, so we really only need to list the first and last letter of the range inside the square brackets, followed by the ‘%’ wildcard allowing for any number of characters after the first letter in the range. Note: A predicate that uses a range will not work with the ‘=’ operator (equals sign). It will neither raise an error, nor produce a result set. --Bad query (will not error or return any records) SELECT * FROM Employee WHERE FirstName = '[A-K]%' Question: You want to find all first names that start with the letters A-M in your Customer table and end with the letter Z. Which SQL code would you use? a. SELECT * FROM Customer WHERE FirstName LIKE 'm%z' b. SELECT * FROM Customer WHERE FirstName LIKE 'a-m%z' c. SELECT * FROM Customer WHERE FirstName LIKE 'a-m%z' d. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]%z' e. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]z%' f. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]%z' g. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]z%' Contest Leave a valid answer before June 18, 2013 in the comment section. 5 winners will be selected from all the valid answers and will receive Joes 2 Pros Book #1. 1 Lucky person will get a surprise gift from Joes 2 Pros. The contest is open for all the countries where Amazon ships the book (USA, UK, Canada, India and many others). Special Note: Read all the options before you provide valid answer as there is a small trick hidden in answers. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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