Search Results

Search found 6183 results on 248 pages for 'double brace initializati'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 69/248 | < Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >

  • C++ choose function by return type.

    - by anon
    I realize standard C++ only picks functions by argument type, not return type. I.e I can do something like: void func(int); void func(double); but not double func(); int func(); Where in the former, it's clear, in the latter, it's ambigious. Are there any extensions that lets me tell C++ to pick which function to use also by return type? Thanks!

    Read the article

  • C# drawing and invalidating 2 lines to meet

    - by BlueMonster
    If i have 2 lines on a page as such: e.Graphics.DrawLine(blackPen, w, h, h, w); e.Graphics.DrawLine(blackPen, w2, h2, h2, w2); how would i animate the first line to reach the second line's position? I have the following method which calculates the distance between two points (i'm assuming i would use this?) public int Distance2D(int x1, int y1, int x2, int y2) { // ______________________ //d = &#8730; (x2-x1)^2 + (y2-y1)^2 // //Our end result int result = 0; //Take x2-x1, then square it double part1 = Math.Pow((x2 - x1), 2); //Take y2-y1, then sqaure it double part2 = Math.Pow((y2 - y1), 2); //Add both of the parts together double underRadical = part1 + part2; //Get the square root of the parts result = (int)Math.Sqrt(underRadical); //Return our result return result; } How would i re-draw the line (on a timer) to reach the second line's position? I've looked a lot into XAML (story-boarding) and such - but i want to know how to do this on my own. Any ideas? I know i would need a method which runs in a loop re-drawing the line after moving the position a tid bit. I would have to call Invalidate() in order to make the line appear as though it's moving... but how would i do this? how would i move that line slowly over to the other line? I'm pretty sure i'd have to use double buffering if i'm doing this as well... as such: SetStyle(ControlStyles.DoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint, true); This doesn't quiet work, i'm not quiet sure how to fix it. Any ideas? protected override void OnPaint(PaintEventArgs e) { Distance2D(w, h, w2, h2); if (w2 != w && h2 != h) { e.Graphics.DrawLine(blackPen, (w * (int)frame), (h * (int)frame), (h * (int)frame), (w * (int)frame)); e.Graphics.DrawLine(blackPen, w2, h2, h2, w2); } else { t.Abort(); } base.OnPaint(e); } public void MoveLine() { for (int i = 0; i < 126; i++) { frame += .02; Invalidate(); Thread.Sleep(30); } } private void button1_Click(object sender, EventArgs e) { t = new Thread(new ThreadStart(MoveLine)); t.Start(); }

    Read the article

  • Collision Detection probelm (intersection with plane)

    - by Demi
    I'm doing a scene using openGL (a house). I want to do some collision detection, mainly with the walls in the house. I have tried the following code: // a plane is represented with a normal and a position in space Vector planeNor(0,0,1); Vector position(0,0,-10); Plane p(planeNor,position); Vector vel(0,0,-1); double lamda; // this is the intersection point Vector pNormal; // the normal of the intersection // this method is from Nehe's Lesson 30 coll= p.TestIntersionPlane(vel,Z,lamda,pNormal); glPushMatrix(); glBegin(GL_QUADS); if(coll) glColor3f(1,0,0); else glColor3f(1,1,1); glVertex3d(0,0,-10); glVertex3d(3,0,-10); glVertex3d(3,3,-10); glVertex3d(0,3,-10); glEnd(); glPopMatrix(); Nehe's method: #define EPSILON 1.0e-8 #define ZERO EPSILON bool Plane::TestIntersionPlane(const Vector3 & position,const Vector3 & direction, double& lamda, Vector3 & pNormal) { double DotProduct=direction.scalarProduct(normal); // Dot Product Between Plane Normal And Ray Direction double l2; // Determine If Ray Parallel To Plane if ((DotProduct<ZERO)&&(DotProduct>-ZERO)) return false; l2=(normal.scalarProduct(position))/DotProduct; // Find Distance To Collision Point if (l2<-ZERO) // Test If Collision Behind Start return false; pNormal= normal; lamda=l2; return true; } Z is initially (0,0,0) and every time I move the camera towards the plane, I reduce its z component by 0.1 (i.e. Z.z-=0.1 ). I know that the problem is with the vel vector, but I can't figure out what the right value should be. Can anyone please help me?

    Read the article

  • Should we use temporary variables for the returned values of functions?

    - by totymedli
    I thought about this: Is there a performance difference in these two practices: Store the return value of a function in a temporary variable than give that variable as a parameter to another function. Put the function into the other function. Specification Assuming all classes and functions are written correctly. Case 1. ClassA a = function1(); ClassB b = function2(a); function3(b); Case 2. function3(function2(function1())); I know there aren't a big difference with only one run, but supposed that we could run this a lot of times in a loop, I created some tests. Test #include <iostream> #include <ctime> #include <math.h> using namespace std; int main() { clock_t start = clock(); clock_t ends = clock(); // Case 1. start = clock(); for (int i=0; i<10000000; i++) { double a = cos(1); double b = pow(a, 2); sqrt(b); } ends = clock(); cout << (double) (ends - start) / CLOCKS_PER_SEC << endl; // Case 2. start = clock(); for (int i=0; i<10000000; i++) sqrt(pow(cos(1),2)); ends = clock(); cout << (double) (ends - start) / CLOCKS_PER_SEC << endl; return 0; } Results Case 1 = 6.375 Case 2 = 0.031 Why is the first one is much slower, and if the second one is faster why dont we always write code that way? Anyway does the second pratice has a name? I also wondered what happens if I create the variables outside the for loop in the first case, but the result was the same. Why?

    Read the article

  • Mutable objects and hashCode

    - by robert
    Have the following class: public class Member { private int x; private long y; private double d; public Member(int x, long y, double d) { this.x = x; this.y = y; this.d = d; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + x; result = (int) (prime * result + y); result = (int) (prime * result + Double.doubleToLongBits(d)); return result; } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj instanceof Member) { Member other = (Member) obj; return other.x == x && other.y == y && Double.compare(d, other.d) == 0; } return false; } public static void main(String[] args) { Set<Member> test = new HashSet<Member>(); Member b = new Member(1, 2, 3); test.add(b); System.out.println(b.hashCode()); b.x = 0; System.out.println(b.hashCode()); Member first = test.iterator().next(); System.out.println(test.contains(first)); System.out.println(b.equals(first)); System.out.println(test.add(first)); } } It produces the following results: 30814 29853 false true true Because the hashCode depends of the state of the object it can no longer by retrieved properly, so the check for containment fails. The HashSet in no longer working properly. A solution would be to make Member immutable, but is that the only solution? Should all classes added to HashSets be immutable? Is there any other way to handle the situation? Regards.

    Read the article

  • Getting An Array Result From A C# Method

    - by Soo
    I am trying to write some code to return an array in C#, but don't know the proper syntax. I think my method is set up correctly, but to set an array to the result of the method is what I'm having difficulty with. Method Declaration: double[,] function(double variable) { ... code ... return array }

    Read the article

  • Flexible array member in C-structure

    - by Arpan
    Quoting from the C-std section 6.7.2.1, struct s { int n; double d[]; }; This is a valid structure declaration. I am looking for some practical use of this kind of syntax. To be precise, how is this construct any more or less powerful than keeping a double* as the 2nd element? Or is this another case of 'you-can-do-it-in-multiple-ways'? Arpan

    Read the article

  • How to get Ponter/Reference semantics in Scala.

    - by Lukasz Lew
    In C++ I would just take a pointer (or reference) to arr[idx]. In Scala I find myself creating this class to emulate a pointer semantic. class SetTo (val arr : Array[Double], val idx : Int) { def apply (d : Double) { arr(idx) = d } } Isn't there a simpler way? Doesn't Array class have a method to return some kind of reference to a particular field?

    Read the article

  • Comparator interface

    - by 1ace1
    ok I was going to edit my previous question but i wasnt sure if it was the right way to do it so i'll just give another question about Comparator, now i want to be able to sort with different ways. I have a bank checks and i want to sort with checkNumber then checkAmount i managed to do it with checkNumber but couldnt figure out how with checkAmount here is how i did it for checkNumber: import java.util.Comparator; public class Check implements Comparator { private int checkNumber; private String description; private double checkAmount; public Check() { } public Check(int newCheckNumber, double newAmountNumber) { setCheckNumber(newCheckNumber); setAmountNumber(newAmountNumber); } public String toString() { return checkNumber + "\t\t" + checkAmount; } public void setCheckNumber(int checkNumber) { this.checkNumber = checkNumber; } public int getCheckNumber() { return checkNumber; } public void setAmountNumber(double amountNumber) { this.checkAmount = amountNumber; } public double getAmountNumber() { return checkAmount; } @Override public int compare(Object obj1, Object obj2) { int value1 = ((Check) obj1).getCheckNumber(); int value2 = ((Check) obj2).getCheckNumber(); int result = 0; if (value1 > value2){ result = 1; } else if(value1 < value2){ result = -1; } return result; } } import java.util.ArrayList; import java.util.Collections; import test.CheckValue; public class TestCheck { public static void main(String[] args) { ArrayList List = new ArrayList(); List.add(new Check(445, 55.0)); List.add(new Check(101,43.12)); List.add(new Check(110,101.0)); List.add(new Check(553,300.21)); List.add(new Check(123,32.1)); Collections.sort(List, new Check()); System.out.println("Check Number - Check Amount"); for (int i = 0; i < List.size(); i++){ System.out.println(List.get(i)); } } } thank you very much in advance and please tell me if im submiting things in the wrong way.

    Read the article

  • Speeding up Math calculations in Java

    - by Simon
    I have a neural network written in Java which uses a sigmoid transfer function defined as follows: private static double sigmoid(double x) { return 1 / (1 + Math.exp(-x)); } and this is called many times during training and computation using the network. Is there any way of speeding this up? It's not that it's slow, it's just that it is used a lot, so a small optimisation here would be a big overall gain.

    Read the article

  • Sort std::vector by an element inside?

    - by user146780
    I currently have a std::vector which holds std::vector of double. I'd want to sort it by the second element of the double vectore. ex: instead of sorting by MyVec[0] or myvec[1] I wat it to sort myVec[0] and myvec[1] based on myvec[0][1] myvec[1][1]. Basically sort by a contained value, not the objects in it. so if myvec[0][1] is less than myvec[1][1] then myvec[0] and myvec[1] will swap. Thanks

    Read the article

  • Parsing command line options in Perl

    - by Jay Gridley
    Hi guys, I am parsing command line options in Perl using Getopt::Long. I am forced to use prefix - (one dash) for short commands (-s) and -- (double dash) for long commands (ex. --input=file), but problem is, that there is one special option (-r=) so it is long option for its requirement for argument, but it has to have one dash (-) prefix not double dash (--) like other long options. Is possible to setup Getopt::Long to accept these?

    Read the article

  • Floating point arithmetics restricted to integers

    - by user396672
    I use doubles for a uniform implementation of some arithmetic calculations. These calculations may be actually applied to integers too, but there are no C++-like templates in Java and I don't want to duplicate the implementation code, so I simply use "double" version for ints. Does JVM spec guarantees the correctness of integer operations such a <=,=, +, -, *, and / (in case of remainder==0) when the operations are emulated as corresponding floating point ops? (Any integer, of course, has reasonable size to be represented in double's mantissa)

    Read the article

  • round() for float in C++

    - by Roddy
    I need a simple floating point rounding function, thus: double round(double); round(0.1) = 0 round(-0.1) = 0 round(-0.9) = -1 I can find ceil() and floor() in the math.h - but not round(). Is it present in the standard C++ library under another name, or is it missing??

    Read the article

  • Constructors from extended class in Java

    - by Crystal
    I'm having some trouble with a hw assignment. In one assignment, we had to create a Person class. Mine was: public class Person { String firstName; String lastName; String telephone; String email; public Person() { firstName = ""; lastName = ""; telephone = ""; email = ""; } public Person(String firstName) { this.firstName = firstName; } public Person(String firstName, String lastName, String telephone, String email) { this.firstName = firstName; this.lastName = lastName; this.telephone = telephone; this.email = email; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getTelephone() { return telephone; } public void setTelephone(String telephone) { this.telephone = telephone; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public boolean equals(Object otherObject) { // a quick test to see if the objects are identical if (this == otherObject) { return true; } // must return false if the explicit parameter is null if (otherObject == null) { return false; } if (!(otherObject instanceof Person)) { return false; } Person other = (Person) otherObject; return firstName.equals(other.firstName) && lastName.equals(other.lastName) && telephone.equals(other.telephone) && email.equals(other.email); } public int hashCode() { return 7 * firstName.hashCode() + 11 * lastName.hashCode() + 13 * telephone.hashCode() + 15 * email.hashCode(); } public String toString() { return getClass().getName() + "[firstName = " + firstName + '\n' + "lastName = " + lastName + '\n' + "telephone = " + telephone + '\n' + "email = " + email + "]"; } } Now we have to extend that class and use that class in our constructor. The function protoype is: public CarLoan(Person client, double vehiclePrice, double downPayment, double salesTax, double interestRate, CAR_LOAN_TERMS length) I'm confused on how I use the Person constructor from the superclass. I cannot necessarily do super(client); in my constructor which is what the book did with some primitive types in their example. Not sure what the correct thing to do is... Any thoughts? Thanks!

    Read the article

  • Optimizing division/exponential calculation

    - by Saltheart
    I've inherited a Visual Studio/VB.Net numerical simulation project that has a likely inefficient calculation. Profiling indicates that the function is called a lot (1 million times plus) and spends about 50% of the overall calculation within this function. Here is the problematic portion Result = (A * (E ^ C)) / (D ^ C * B) (where A-C are local double variables and D & E global double variables) Result is then compared to a threshold which might have additional improvements as well, but I'll leave them another day any thoughts or help would be appreciated Steve

    Read the article

  • C++, strange behavior reusing variable name

    - by aaa
    hello. I have following snippet: { double scale = 3; // not used? { double scale = 4*scale; // what is RHS scale? for (...) { // scale is 0 here, using g++ } } } moreover, g++ reports first scale is not used. how is second scale initialize? What should be correct behavior? thanks

    Read the article

  • What does @@variable mean in Ruby?

    - by Andrew
    What are Ruby variables preceded with double at signs (@@)? My understanding of a variable preceded with an at sign is that it is an instance variable, like this in PHP: PHP version class Person { public $name; public function setName($name) { $this->name = $name; } public function getName() { return $this->name; } } Ruby equivalent class Person def set_name(name) @name = name end def get_name() @name end end What does the double at sign @@ mean, and how does it differ from a single at sign?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >