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• Design suggestions needed to create a MathBuilder framework

  - by Darf Zon

  Let explain what I'm trying to create. I'm creating a framework, the idea is to provide base classes to generate a math problem. Why do I need this framework? Because at first time, I realized when I create a new math problem I always do the same steps. Configuration settings such range numbers. For example if I'm developing multiplications, in beginner level only generate the first number between 2-5 or in advanced level, the first number will be between 6- 9, for example. Generate problem method. All the time I need to invoke a method like this to generate the problem. This one receives the configuration settings and generate the number according to them. And generate the object with the respective data. Validate the problem. Sometimes the problem generated is not valid. For example, supposed I'm creating fractions in most simplified, if I receive 2/4, the program should detect that this is not valid and must generate another like this one, 1/4. Load the view. All of them, have a custom view (please watch below the images). All of the problems must know how to CHECK if the user result is correct. All of this problems has answers. Some of them just require one answer, anothers may require more than one, so I guess a way to maintain flexibility to the developer has all the answers he wanna used. At the beginning I started using PRISM. Generate modules for each math problem was the idea and load it in the main system. I guess are the most important things of this idea. Let me showing some problems which I create in a WPF standalone program. Here I have a math problem about areas. When I generate the problem a set to the view the object and it draw it. In beginner level, I set in the configuration settings that just load square types. But in advance level, can load triangles and squares randomly. In this another, generate a binary problem like addition, subtraction, multiplication or division. Above just generate a single problem. The idea of this is to show a test o quiz, I mean get a worksheet (this I call as a collection of problems) where the user can answer it. I hope gets the idea with my ugly drawing. How to load this math problems? As I said above, I started using PRISM, and each module contains a math problem kind. This is a snapshot of my first demo. Below show the modules loaded, and center the respective configurations or levels. Until momment, I have no idea to start creating this software. I just know that I need a question | problem class, response class, user class. But I get lost about what properties should have to contain in it. Please give a little hand of this framework. I put much effort on this question, so if any isn't clear, let me know to clarify it.

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• Starting to create a MathBuilder framework, help to start creating the design

  - by Darf Zon

  Let explain what I'm trying to create. I'm creating a framework, the idea is to provide base classes to generate a math problem. Why do I need this framework? Because at first time, I realized when I create a new math problem I always do the same steps. Configuration settings such range numbers. For example if I'm developing multiplications, in beginner level only generate the first number between 2-5 or in advanced level, the first number will be between 6- 9, for example. Generate problem method. All the time I need to invoke a method like this to generate the problem. This one receives the configuration settings and generate the number according to them. And generate the object with the respective data. Validate the problem. Sometimes the problem generated is not valid. For example, supposed I'm creating fractions in most simplified, if I receive 2/4, the program should detect that this is not valid and must generate another like this one, 1/4. Load the view. All of them, have a custom view (please watch below the images). All of the problems must know how to CHECK if the user result is correct. All of this problems has answers. Some of them just require one answer, anothers may require more than one, so I guess a way to maintain flexibility to the developer has all the answers he wanna used. At the beginning I started using PRISM. Generate modules for each math problem was the idea and load it in the main system. I guess are the most important things of this idea. Let me showing some problems which I create in a WPF standalone program. Here I have a math problem about areas. When I generate the problem a set to the view the object and it draw it. In beginner level, I set in the configuration settings that just load square types. But in advance level, can load triangles and squares randomly. In this another, generate a binary problem like addition, subtraction, multiplication or division. Above just generate a single problem. The idea of this is to show a test o quiz, I mean get a worksheet (this I call as a collection of problems) where the user can answer it. I hope gets the idea with my ugly drawing. How to load this math problems? As I said above, I started using PRISM, and each module contains a math problem kind. This is a snapshot of my first demo. Below show the modules loaded, and center the respective configurations or levels. Until momment, I have no idea to start creating this software. I just know that I need a question | problem class, response class, user class. But I get lost about what properties should have to contain in it. Please give a little hand of this framework. I put much effort on this question, so if any isn't clear, let me know to clarify it.

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• rotate player based off of joystick

  - by pengume

  Hey everyone I have this game that i am making in android and I have a touch screen joystick that moves the player around based on the joysticks position. I cant figure out how to also get the player to rotate at the same angle of the joystick. so when the joystick is to the left the players bitmap is rotated to the left as well. Maybe someone here has some sample code I could look at here is the joysticks class that I am using. `public class GameControls implements OnTouchListener { public float initx = DroidzActivity.screenWidth - 45; //255; // 320 og 425 public float inity = DroidzActivity.screenHeight - 45;//425; // 480 og 267 public Point _touchingPoint = new Point( DroidzActivity.screenWidth - 45, DroidzActivity.screenHeight - 45); public Point _pointerPosition = new Point(DroidzActivity.screenWidth - 100, DroidzActivity.screenHeight - 100); // ogx 220 ogy 150 private Boolean _dragging = false; private boolean attackMode = false; @Override public boolean onTouch(View v, MotionEvent event) { update(event); return true; } private MotionEvent lastEvent; public boolean ControlDragged; private static double angle; public void update(MotionEvent event) { if (event == null && lastEvent == null) { return; } else if (event == null && lastEvent != null) { event = lastEvent; } else { lastEvent = event; } // drag drop if (event.getAction() == MotionEvent.ACTION_DOWN) { if ((int) event.getX() > 0 && (int) event.getX() < 50 && (int) event.getY() > DroidzActivity.screenHeight - 160 && (int) event.getY() < DroidzActivity.screenHeight - 0) { setAttackMode(true); } else { _dragging = true; } } else if (event.getAction() == MotionEvent.ACTION_UP) { if(isAttackMode()){ setAttackMode(false); } _dragging = false; } if (_dragging) { ControlDragged = true; // get the pos _touchingPoint.x = (int) event.getX(); _touchingPoint.y = (int) event.getY(); // Log.d("GameControls", "x = " + _touchingPoint.x + " y = " //+ _touchingPoint.y); // bound to a box if (_touchingPoint.x < DroidzActivity.screenWidth - 75) { // og 400 _touchingPoint.x = DroidzActivity.screenWidth - 75; } if (_touchingPoint.x > DroidzActivity.screenWidth - 15) {// og 450 _touchingPoint.x = DroidzActivity.screenWidth - 15; } if (_touchingPoint.y < DroidzActivity.screenHeight - 75) {// og 240 _touchingPoint.y = DroidzActivity.screenHeight - 75; } if (_touchingPoint.y > DroidzActivity.screenHeight - 15) {// og 290 _touchingPoint.y = DroidzActivity.screenHeight - 15; } // get the angle setAngle(Math.atan2(_touchingPoint.y - inity, _touchingPoint.x - initx) / (Math.PI / 180)); // Move the ninja in proportion to how far // the joystick is dragged from its center _pointerPosition.y += Math.sin(getAngle() * (Math.PI / 180)) * (_touchingPoint.x / 70); // og 180 70 _pointerPosition.x += Math.cos(getAngle() * (Math.PI / 180)) * (_touchingPoint.x / 70); // make the pointer go thru if (_pointerPosition.x > DroidzActivity.screenWidth) { _pointerPosition.x = 0; } if (_pointerPosition.x < 0) { _pointerPosition.x = DroidzActivity.screenWidth; } if (_pointerPosition.y > DroidzActivity.screenHeight) { _pointerPosition.y = 0; } if (_pointerPosition.y < 0) { _pointerPosition.y = DroidzActivity.screenHeight; } } else if (!_dragging) { ControlDragged = false; // Snap back to center when the joystick is released _touchingPoint.x = (int) initx; _touchingPoint.y = (int) inity; // shaft.alpha = 0; } } public void setAttackMode(boolean attackMode) { this.attackMode = attackMode; } public boolean isAttackMode() { return attackMode; } public void setAngle(double angle) { this.angle = angle; } public static double getAngle() { return angle; } }` I should also note that the player has animations based on when he is moving or attacking.

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• AABB vs OBB Collision Resolution jitter on corners

  - by patt4179

  I've implemented a collision library for a character who is an AABB and am resolving collisions between AABB vs AABB and AABB vs OBB. I wanted slopes for certain sections, so I've toyed around with using several OBBs to make one, and it's working great except for one glaring issue; The collision resolution on the corner of an OBB makes the player's AABB jitter up and down constantly. I've tried a few things I've thought of, but I just can't wrap my head around what's going on exactly. Here's a video of what's happening as well as my code: Here's the function to get the collision resolution (I'm likely not doing this the right way, so this may be where the issue lies): public Vector2 GetCollisionResolveAmount(RectangleCollisionObject resolvedObject, OrientedRectangleCollisionObject b) { Vector2 overlap = Vector2.Zero; LineSegment edge = GetOrientedRectangleEdge(b, 0); if (!SeparatingAxisForRectangle(edge, resolvedObject)) { LineSegment rEdgeA = new LineSegment(), rEdgeB = new LineSegment(); Range axisRange = new Range(), rEdgeARange = new Range(), rEdgeBRange = new Range(), rProjection = new Range(); Vector2 n = edge.PointA - edge.PointB; rEdgeA.PointA = RectangleCorner(resolvedObject, 0); rEdgeA.PointB = RectangleCorner(resolvedObject, 1); rEdgeB.PointA = RectangleCorner(resolvedObject, 2); rEdgeB.PointB = RectangleCorner(resolvedObject, 3); rEdgeARange = ProjectLineSegment(rEdgeA, n); rEdgeBRange = ProjectLineSegment(rEdgeB, n); rProjection = GetRangeHull(rEdgeARange, rEdgeBRange); axisRange = ProjectLineSegment(edge, n); float axisMid = (axisRange.Maximum + axisRange.Minimum) / 2; float projectionMid = (rProjection.Maximum + rProjection.Minimum) / 2; if (projectionMid > axisMid) { overlap.X = axisRange.Maximum - rProjection.Minimum; } else { overlap.X = rProjection.Maximum - axisRange.Minimum; overlap.X = -overlap.X; } } edge = GetOrientedRectangleEdge(b, 1); if (!SeparatingAxisForRectangle(edge, resolvedObject)) { LineSegment rEdgeA = new LineSegment(), rEdgeB = new LineSegment(); Range axisRange = new Range(), rEdgeARange = new Range(), rEdgeBRange = new Range(), rProjection = new Range(); Vector2 n = edge.PointA - edge.PointB; rEdgeA.PointA = RectangleCorner(resolvedObject, 0); rEdgeA.PointB = RectangleCorner(resolvedObject, 1); rEdgeB.PointA = RectangleCorner(resolvedObject, 2); rEdgeB.PointB = RectangleCorner(resolvedObject, 3); rEdgeARange = ProjectLineSegment(rEdgeA, n); rEdgeBRange = ProjectLineSegment(rEdgeB, n); rProjection = GetRangeHull(rEdgeARange, rEdgeBRange); axisRange = ProjectLineSegment(edge, n); float axisMid = (axisRange.Maximum + axisRange.Minimum) / 2; float projectionMid = (rProjection.Maximum + rProjection.Minimum) / 2; if (projectionMid > axisMid) { overlap.Y = axisRange.Maximum - rProjection.Minimum; overlap.Y = -overlap.Y; } else { overlap.Y = rProjection.Maximum - axisRange.Minimum; } } return overlap; } And here is what I'm doing to resolve it right now: if (collisionDetection.OrientedRectangleAndRectangleCollide(obb, player.PlayerCollision)) { var resolveAmount = collisionDetection.GetCollisionResolveAmount(player.PlayerCollision, obb); if (Math.Abs(resolveAmount.Y) < Math.Abs(resolveAmount.X)) { var roundedAmount = (float)Math.Floor(resolveAmount.Y); player.PlayerCollision._position.Y -= roundedAmount; } else if (Math.Abs(resolveAmount.Y) <= 30.0f) //Catch cases where the player should be able to step over the top of something { var roundedAmount = (float)Math.Floor(resolveAmount.Y); player.PlayerCollision._position.Y -= roundedAmount; } else { var roundedAmount = (float)Math.Floor(resolveAmount.X); player.PlayerCollision._position.X -= roundedAmount; } } Can anyone see what might be the issue here, or has anyone experienced this before that knows a possible solution? I've tried for a few days to figure this out on my own, but I'm just stumped.

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• User Input That Involves A ' ' Causes A Substring Out Of Range Error

  - by Greenhouse Gases

  Hi Stackoverflow people. You have already helped me quite a bit but near the end of writing this program I have somewhat of a bug. You see in order to read in city names with a space in from a text file I use a '/' that is then replaced by the program for a ' ' (and when the serializer runs the opposite happens for next time the program is run). The problem is when a user inputs a name too add, search for, or delete that contains a space, for instance 'New York' I get a Debug Assertion Error with a substring out of range expression. I have a feeling it's to do with my correctCase function, or setElementsNull that looks at the string until it experiences a null element in the array, however ' ' is not null so I'm not sure how to fix this and I'm going a bit insane. Any help would be much appreciated. Here is my code: // U08221.cpp : main project file. #include "stdafx.h" #include <_iostream> #include <_string> #include <_fstream> #include <_cmath> using namespace std; class locationNode { public: string nodeCityName; double nodeLati; double nodeLongi; locationNode* Next; locationNode(string nameOf, double lat, double lon) { this->nodeCityName = nameOf; this->nodeLati = lat; this->nodeLongi = lon; this->Next = NULL; } locationNode() // NULL constructor { } void swapProps(locationNode *node2) { locationNode place; place.nodeCityName = this->nodeCityName; place.nodeLati = this->nodeLati; place.nodeLongi = this->nodeLongi; this->nodeCityName = node2->nodeCityName; this->nodeLati = node2->nodeLati; this->nodeLongi = node2->nodeLongi; node2->nodeCityName = place.nodeCityName; node2->nodeLati = place.nodeLati; node2->nodeLongi = place.nodeLongi; } void modify(string name) { this->nodeCityName = name; } void modify(double latlon, int mod) { switch(mod) { case 2: this->nodeLati = latlon; break; case 3: this->nodeLongi = latlon; break; } } void correctCase() // Correct upper and lower case letters of input { int MAX_SIZE = 35; int firstLetVal = this->nodeCityName[0], letVal; int n = 1; // variable for name index from second letter onwards if((this->nodeCityName[0] >90) && (this->nodeCityName[0] < 123)) // First letter is lower case { firstLetVal = firstLetVal - 32; // Capitalise first letter this->nodeCityName[0] = firstLetVal; } while(this->nodeCityName[n] != NULL) { if((this->nodeCityName[n] >= 65) && (this->nodeCityName[n] <= 90)) { if(this->nodeCityName[n - 1] != 32) { letVal = this->nodeCityName[n] + 32; this->nodeCityName[n] = letVal; } } n++; } } }; Here is the main part of the program: // U08221.cpp : main project file. #include "stdafx.h" #include "Locations2.h" #include <_iostream> #include <_string> #include <_fstream> #include <_cmath> using namespace std; #define pi 3.14159265358979323846264338327950288 #define radius 6371 #define gig 1073741824 //size of a gigabyte in bytes int n = 0,x, locationCount = 0, MAX_SIZE = 35 , g = 0, i = 0, modKey = 0, xx; string cityNameInput, alter; char targetCity[35], skipKey = ' '; double lat1, lon1, lat2, lon2, dist, dummy, modVal, result; bool acceptedInput = false, match = false, nodeExists = false;// note: addLocation(), set to true to enable user input as opposed to txt file locationNode *temp, *temp2, *example, *seek, *bridge, *start_ptr = NULL; class Menu { int junction; public: /* Convert decimal degrees to radians */ public: void setElementsNull(char cityParam[]) { int y=0; while(cityParam[y] != NULL) { y++; } while(y < MAX_SIZE) { cityParam[y] = NULL; y++; } } void correctCase(string name) // Correct upper and lower case letters of input { int MAX_SIZE = 35; int firstLetVal = name[0], letVal; int n = 1; // variable for name index from second letter onwards if((name[0] >90) && (name[0] < 123)) // First letter is lower case { firstLetVal = firstLetVal - 32; // Capitalise first letter name[0] = firstLetVal; } while(name[n] != NULL) { if((name[n] >= 65) && (name[n] <= 90)) { letVal = name[n] + 32; name[n] = letVal; } n++; } for(n = 0; targetCity[n] != NULL; n++) { targetCity[n] = name[n]; } } bool nodeExistTest(char targetCity[]) // see if entry is present in the database { match = false; seek = start_ptr; int letters = 0, letters2 = 0, x = 0, y = 0; while(targetCity[y] != NULL) { letters2++; y++; } while(x <= locationCount) // locationCount is number of entries currently in list { y=0, letters = 0; while(seek->nodeCityName[y] != NULL) // count letters in the current name { letters++; y++; } if(letters == letters2) // same amount of letters in the name { y = 0; while(y <= letters) // compare each letter against one another { if(targetCity[y] == seek->nodeCityName[y]) { match = true; y++; } else { match = false; y = letters + 1; // no match, terminate comparison } } } if(match) { x = locationCount + 1; //found match so terminate loop } else{ if(seek->Next != NULL) { bridge = seek; seek = seek->Next; x++; } else { x = locationCount + 1; // end of list so terminate loop } } } return match; } double deg2rad(double deg) { return (deg * pi / 180); } /* Convert radians to decimal degrees */ double rad2deg(double rad) { return (rad * 180 / pi); } /* Do the calculation */ double distance(double lat1, double lon1, double lat2, double lon2, double dist) { dist = sin(deg2rad(lat1)) * sin(deg2rad(lat2)) + cos(deg2rad(lat1)) * cos(deg2rad(lat2)) * cos(deg2rad(lon1 - lon2)); dist = acos(dist); dist = rad2deg(dist); dist = (radius * pi * dist) / 180; return dist; } void serialise() { // Serialize to format that can be written to text file fstream outfile; outfile.open("locations.txt",ios::out); temp = start_ptr; do { for(xx = 0; temp->nodeCityName[xx] != NULL; xx++) { if(temp->nodeCityName[xx] == 32) { temp->nodeCityName[xx] = 47; } } outfile << endl << temp->nodeCityName<< " "; outfile<<temp->nodeLati<< " "; outfile<<temp->nodeLongi; temp = temp->Next; }while(temp != NULL); outfile.close(); } void sortList() // do this { int changes = 1; locationNode *node1, *node2; while(changes > 0) // while changes are still being made to the list execute { node1 = start_ptr; node2 = node1->Next; changes = 0; do { xx = 1; if(node1->nodeCityName[0] > node2->nodeCityName[0]) //compare first letter of name with next in list { node1->swapProps(node2); // should come after the next in the list changes++; } else if(node1->nodeCityName[0] == node2->nodeCityName[0]) // if same first letter { while(node1->nodeCityName[xx] == node2->nodeCityName[xx]) // check next letter of name { if((node1->nodeCityName[xx + 1] != NULL) && (node2->nodeCityName[xx + 1] != NULL)) // check next letter until not the same { xx++; } else break; } if(node1->nodeCityName[xx] > node2->nodeCityName[xx]) { node1->swapProps(node2); // should come after the next in the list changes++; } } node1 = node2; node2 = node2->Next; // move to next pair in list } while(node2 != NULL); } } void initialise() { cout << "Populating List..."; ifstream inputFile; inputFile.open ("locations.txt", ios::in); char inputName[35] = " "; double inputLati = 0, inputLongi = 0; //temp = new locationNode(inputName, inputLati, inputLongi); do { inputFile.get(inputName, 35, ' '); inputFile >> inputLati; inputFile >> inputLongi; if(inputName[0] == 10 || 13) //remove linefeed from input { for(int i = 0; inputName[i] != NULL; i++) { inputName[i] = inputName[i + 1]; } } for(xx = 0; inputName[xx] != NULL; xx++) { if(inputName[xx] == 47) // if it is a '/' { inputName[xx] = 32; // replace it for a space } } temp = new locationNode(inputName, inputLati, inputLongi); if(start_ptr == NULL){ // if list is currently empty, start_ptr will point to this node start_ptr = temp; } else { temp2 = start_ptr; // We know this is not NULL - list not empty! while (temp2->Next != NULL) { temp2 = temp2->Next; // Move to next link in chain until reach end of list } temp2->Next = temp; } ++locationCount; // increment counter for number of records in list } while(!inputFile.eof()); cout << "Successful!" << endl << "List contains: " << locationCount << " entries" << endl; inputFile.close(); cout << endl << "*******************************************************************" << endl << "DISTANCE CALCULATOR v2.0\tAuthors: Darius Hodaei, Joe Clifton" << endl; } void menuInput() { char menuChoice = ' '; while(menuChoice != 'Q') { // Menu if(skipKey != 'X') // This is set by case 'S' below if a searched term does not exist but wants to be added { cout << endl << "*******************************************************************" << endl; cout << "Please enter a choice for the menu..." << endl << endl; cout << "(P) To print out the list" << endl << "(O) To order the list alphabetically" << endl << "(A) To add a location" << endl << "(D) To delete a record" << endl << "(C) To calculate distance between two points" << endl << "(S) To search for a location in the list" << endl << "(M) To check memory usage" << endl << "(U) To update a record" << endl << "(Q) To quit" << endl; cout << endl << "*******************************************************************" << endl; cin >> menuChoice; if(menuChoice >= 97) { menuChoice = menuChoice - 32; // Turn the lower case letter into an upper case letter } } skipKey = ' '; //Reset skipKey so that it does not skip the menu switch(menuChoice) { case 'P': temp = start_ptr; // set temp to the start of the list do { if (temp == NULL) { cout << "You have reached the end of the database" << endl; } else { // Display details for what temp points to at that stage cout << "Location : " << temp->nodeCityName << endl; cout << "Latitude : " << temp->nodeLati << endl; cout << "Longitude : " << temp->nodeLongi << endl; cout << endl; // Move on to next locationNode if one exists temp = temp->Next; } } while (temp != NULL); break; case 'O': { sortList(); // pass by reference??? cout << "List reordered alphabetically" << endl; } break; case 'A': char cityName[35]; double lati, longi; cout << endl << "Enter the name of the location: "; cin >> cityName; for(xx = 0; cityName[xx] != NULL; xx++) { if(cityName[xx] == 47) // if it is a '/' { cityName[xx] = 32; // replace it for a space } } if(!nodeExistTest(cityName)) { cout << endl << "Please enter the latitude value for this location: "; cin >> lati; cout << endl << "Please enter the longitude value for this location: "; cin >> longi; cout << endl; temp = new locationNode(cityName, lati, longi); temp->correctCase(); //start_ptr allignment if(start_ptr == NULL){ // if list is currently empty, start_ptr will point to this node start_ptr = temp; } else { temp2 = start_ptr; // We know this is not NULL - list not empty! while (temp2->Next != NULL) { temp2 = temp2->Next; // Move to next link in chain until reach end of list } temp2->Next = temp; } ++locationCount; // increment counter for number of records in list cout << "Location sucessfully added to the database! There are " << locationCount << " location(s) stored" << endl; } else { cout << "Node is already present in the list and so cannot be added again" << endl; } break; case 'D': { junction = 0; locationNode *place; cout << "Enter the name of the city you wish to remove" << endl; cin >> targetCity; setElementsNull(targetCity); correctCase(targetCity); for(xx = 0; targetCity[xx] != NULL; xx++) { if(targetCity[xx] == 47) { targetCity[xx] = 32; } } if(nodeExistTest(targetCity)) //if this node does exist { if(seek == start_ptr) // if it is the first in the list { junction = 1; } if(seek->Next == NULL) // if it is last in the list { junction = 2; } switch(junction) // will alter list accordingly dependant on where the searched for link is { case 1: start_ptr = start_ptr->Next; delete seek; --locationCount; break; case 2: place = seek; seek = bridge; seek->Next = NULL; delete place; --locationCount; break; default: bridge->Next = seek->Next; delete seek; --locationCount; break; } cout << endl << "Link deleted. There are now " << locationCount << " locations." << endl; } else { cout << "That entry does not currently exist" << endl << endl << endl; } } break; case 'C': { char city1[35], city2[35]; cout << "Enter the first city name" << endl; cin >> city1; setElementsNull(city1); correctCase(targetCity); if(nodeExistTest(city1)) { lat1 = seek->nodeLati; lon1 = seek->nodeLongi; cout << "Lati = " << seek->nodeLati << endl << "Longi = " << seek->nodeLongi << endl << endl; } cout << "Enter the second city name" << endl; cin >> city2; setElementsNull(city2); correctCase(targetCity); if(nodeExistTest(city2)) { lat2 = seek->nodeLati; lon2 = seek->nodeLongi; cout << "Lati = " << seek->nodeLati << endl << "Longi = " << seek->nodeLongi << endl << endl; } result = distance (lat1, lon1, lat2, lon2, dist); cout << "The distance between these two locations is " << result << " kilometres." << endl; } break; case 'S': { char choice; cout << "Enter search term..." << endl; cin >> targetCity; setElementsNull(targetCity); correctCase(targetCity); if(nodeExistTest(targetCity)) { cout << "Latitude: " << seek->nodeLati << endl << "Longitude: " << seek->nodeLongi << endl; } else { cout << "Sorry, that city is not currently present in the list." << endl << "Would you like to add this city now Y/N?" << endl; cin >> choice; /*while(choice != ('Y' || 'N')) { cout << "Please enter a valid choice..." << endl; cin >> choice; }*/ switch(choice) { case 'Y': skipKey = 'X'; menuChoice = 'A'; break; case 'N': break; default : cout << "Invalid choice" << endl; break; } } break; } case 'M': { cout << "Locations currently stored: " << locationCount << endl << "Memory used for this: " << (sizeof(start_ptr) * locationCount) << " bytes" << endl << endl << "You can store " << ((gig - (sizeof(start_ptr) * locationCount)) / sizeof(start_ptr)) << " more locations" << endl ; break; } case 'U': { cout << "Enter the name of the Location you would like to update: "; cin >> targetCity; setElementsNull(targetCity); correctCase(targetCity); if(nodeExistTest(targetCity)) { cout << "Select (1) to alter City Name, (2) to alter Longitude, (3) to alter Latitude" << endl; cin >> modKey; switch(modKey) { case 1: cout << "Enter the new name: "; cin >> alter; cout << endl; seek->modify(alter); break; case 2: cout << "Enter the new latitude: "; cin >> modVal; cout << endl; seek->modify(modVal, modKey); break; case 3: cout << "Enter the new longitude: "; cin >> modVal; cout << endl; seek->modify(modVal, modKey); break; default: break; } } else cout << "Location not found" << endl; break; } } } } }; int main(array<System::String ^> ^args) { Menu mm; //mm.initialise(); mm.menuInput(); mm.serialise(); }

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• Why is insertion into my tree faster on sorted input than random input?

  - by Juliet

  Now I've always heard binary search trees are faster to build from randomly selected data than ordered data, simply because ordered data requires explicit rebalancing to keep the tree height at a minimum. Recently I implemented an immutable treap, a special kind of binary search tree which uses randomization to keep itself relatively balanced. In contrast to what I expected, I found I can consistently build a treap about 2x faster and generally better balanced from ordered data than unordered data -- and I have no idea why. Here's my treap implementation: http://pastebin.com/VAfSJRwZ And here's a test program: using System; using System.Collections.Generic; using System.Linq; using System.Diagnostics; namespace ConsoleApplication1 { class Program { static Random rnd = new Random(); const int ITERATION_COUNT = 20; static void Main(string[] args) { List<double> rndTimes = new List<double>(); List<double> orderedTimes = new List<double>(); rndTimes.Add(TimeIt(50, RandomInsert)); rndTimes.Add(TimeIt(100, RandomInsert)); rndTimes.Add(TimeIt(200, RandomInsert)); rndTimes.Add(TimeIt(400, RandomInsert)); rndTimes.Add(TimeIt(800, RandomInsert)); rndTimes.Add(TimeIt(1000, RandomInsert)); rndTimes.Add(TimeIt(2000, RandomInsert)); rndTimes.Add(TimeIt(4000, RandomInsert)); rndTimes.Add(TimeIt(8000, RandomInsert)); rndTimes.Add(TimeIt(16000, RandomInsert)); rndTimes.Add(TimeIt(32000, RandomInsert)); rndTimes.Add(TimeIt(64000, RandomInsert)); rndTimes.Add(TimeIt(128000, RandomInsert)); string rndTimesAsString = string.Join("\n", rndTimes.Select(x => x.ToString()).ToArray()); orderedTimes.Add(TimeIt(50, OrderedInsert)); orderedTimes.Add(TimeIt(100, OrderedInsert)); orderedTimes.Add(TimeIt(200, OrderedInsert)); orderedTimes.Add(TimeIt(400, OrderedInsert)); orderedTimes.Add(TimeIt(800, OrderedInsert)); orderedTimes.Add(TimeIt(1000, OrderedInsert)); orderedTimes.Add(TimeIt(2000, OrderedInsert)); orderedTimes.Add(TimeIt(4000, OrderedInsert)); orderedTimes.Add(TimeIt(8000, OrderedInsert)); orderedTimes.Add(TimeIt(16000, OrderedInsert)); orderedTimes.Add(TimeIt(32000, OrderedInsert)); orderedTimes.Add(TimeIt(64000, OrderedInsert)); orderedTimes.Add(TimeIt(128000, OrderedInsert)); string orderedTimesAsString = string.Join("\n", orderedTimes.Select(x => x.ToString()).ToArray()); Console.WriteLine("Done"); } static double TimeIt(int insertCount, Action<int> f) { Console.WriteLine("TimeIt({0}, {1})", insertCount, f.Method.Name); List<double> times = new List<double>(); for (int i = 0; i < ITERATION_COUNT; i++) { Stopwatch sw = Stopwatch.StartNew(); f(insertCount); sw.Stop(); times.Add(sw.Elapsed.TotalMilliseconds); } return times.Average(); } static void RandomInsert(int insertCount) { Treap<double> tree = new Treap<double>((x, y) => x.CompareTo(y)); for (int i = 0; i < insertCount; i++) { tree = tree.Insert(rnd.NextDouble()); } } static void OrderedInsert(int insertCount) { Treap<double> tree = new Treap<double>((x, y) => x.CompareTo(y)); for(int i = 0; i < insertCount; i++) { tree = tree.Insert(i + rnd.NextDouble()); } } } } And here's a chart comparing random and ordered insertion times in milliseconds: Insertions Random Ordered RandomTime / OrderedTime 50 1.031665 0.261585 3.94 100 0.544345 1.377155 0.4 200 1.268320 0.734570 1.73 400 2.765555 1.639150 1.69 800 6.089700 3.558350 1.71 1000 7.855150 4.704190 1.67 2000 17.852000 12.554065 1.42 4000 40.157340 22.474445 1.79 8000 88.375430 48.364265 1.83 16000 197.524000 109.082200 1.81 32000 459.277050 238.154405 1.93 64000 1055.508875 512.020310 2.06 128000 2481.694230 1107.980425 2.24 I don't see anything in the code which makes ordered input asymptotically faster than unordered input, so I'm at a loss to explain the difference. Why is it so much faster to build a treap from ordered input than random input?

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• ArrayList access

  - by Ricky McQuesten

  So once again I have a question about this program. I want to store transactions that are made in an arraylist and then have an option in the case menu where I can print out those that are stored. I have been researching online and have been unable to find a solution to this, so is this possible and how would I go about doing this? I also want to attach a timestamp to each transaction as well. Here is the code I have so far. So my question is how would I add a timestamp to each withdrawal or deposit, and how would I store each transaction in array list? import java.util.*; public class BankAccount extends Money { //inheritence static String name; public static int acctNum; public static double balance, amount; BankAccount(String name, int accNo, double bal) { this.name = name; this.acctNum = accNo; this.balance = bal; } void display() { System.out.println("Your Name:" + name); System.out.println("Your Account Number:" + acctNum); System.out.println("Your Current Account Balance:" + Money.getBalance()); } void displayBalance() { System.out.println("Balance:" + balance); } } import java.util.Scanner; /** * * @author Ricky */ public class Money { public static int accountNumber; public static double balance; static double amount; static String name; public void setDeposit(double amount) { balance = balance + amount; if (amount < 0) { System.out.println("Invalid"); } } public double getDeposit() { return 1; } public void setBalance(double b) { balance = b; } public static double getBalance() { return balance; } public void setWithdraw(double amount) { if (balance < amount) { System.out.println("Not enough funds."); } else if(amount < 0) { System.out.println("Invalid"); } else { balance = balance - amount; } } public double getWithdraw() { return 1; } } import java.util.*; public class Client { public static void main(String args[]) { int n = 0; int count; String trans; ArrayList<String> transaction= new ArrayList<String>(n); Scanner input = new Scanner(System.in); System.out.println("Welcome to First National Bank"); System.out.println("Please enter your name: "); String cusName = input.nextLine(); System.out.println("You will now be assigned an account number."); Random randomGenerator = new Random(); int accNo = randomGenerator.nextInt(100000); //random number System.out.println("Your account number is: " + accNo); System.out.println("Please enter your initial account balance: "); Double balance = input.nextDouble(); BankAccount b1 = new BankAccount(cusName, accNo, balance); b1.setBalance(balance); int menu; /*System.out.println("Menu"); System.out.println("1. Deposit Amount"); System.out.println("2. Withdraw Amount"); System.out.println("3. Display Information"); System.out.println("4. Exit");*/ boolean quit = false; do { System.out.println("*******Menu*******"); System.out.println("1. Deposit Amount"); // menu to take input from user System.out.println("2. Withdraw Amount"); System.out.println("3. Display Information"); System.out.println("4. Exit"); System.out.print("Please enter your choice: "); menu = input.nextInt(); switch (menu) { case 1: System.out.print("Enter depost amount:"); b1.setDeposit(input.nextDouble()); b1.getDeposit(); transaction.add(trans); break; case 2: System.out.println("Current Account Balance=" + b1.getBalance()); System.out.print("Enter withdrawal amount:"); b1.setWithdraw(input.nextDouble()); b1.getWithdraw(); transaction.add(trans); break; // switch statments to do a loop case 3: b1.display(); break; case 4: quit = true; break; } } while (!quit); } } public class Date { static Date time = new Date(); }

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• Pass a Delphi class to a C++ function/method that expects a class with __thiscall methods.

  - by Alan G.

  I have some MSVC++ compiled DLL's for which I have created COM-like (lite) interfaces (abstract Delphi classes). Some of those classes have methods that need pointers to objects. These C++ methods are declared with the __thiscall calling convention (which I cannot change), which is just like __stdcall, except a this pointer is passed on the ECX register. I create the class instance in Delphi, then pass it on to the C++ method. I can set breakpoints in Delphi and see it hitting the exposed __stdcall methods in my Delphi class, but soon I get a STATUS_STACK_BUFFER_OVERRUN and the app has to exit. Is it possible to emulate/deal with __thiscall on the Delphi side of things? If I pass an object instantiated by the C++ system then all is good, and that object's methods are called (as would be expected), but this is useless - I need to pass Delphi objects. Edit 2010-04-19 18:12 This is what happens in more detail: The first method called (setLabel) exits with no error (though its a stub method). The second method called (init), enters then dies when it attempts to read the vol parameter. C++ Side #define SHAPES_EXPORT __declspec(dllexport) // just to show the value class SHAPES_EXPORT CBox { public: virtual ~CBox() {} virtual void init(double volume) = 0; virtual void grow(double amount) = 0; virtual void shrink(double amount) = 0; virtual void setID(int ID = 0) = 0; virtual void setLabel(const char* text) = 0; }; Delphi Side IBox = class public procedure destroyBox; virtual; stdcall; abstract; procedure init(vol: Double); virtual; stdcall; abstract; procedure grow(amount: Double); virtual; stdcall; abstract; procedure shrink(amount: Double); virtual; stdcall; abstract; procedure setID(val: Integer); virtual; stdcall; abstract; procedure setLabel(text: PChar); virtual; stdcall; abstract; end; TMyBox = class(IBox) protected FVolume: Double; FID: Integer; FLabel: String; // public constructor Create; destructor Destroy; override; // BEGIN Virtual Method implementation procedure destroyBox; override; stdcall; // empty - Dont need/want C++ to manage my Delphi objects, just call their methods procedure init(vol: Double); override; stdcall; // FVolume := vol; procedure grow(amount: Double); override; stdcall; // Inc(FVolume, amount); procedure shrink(amount: Double); override; stdcall; // Dec(FVolume, amount); procedure setID(val: Integer); override; stdcall; // FID := val; procedure setLabel(text: PChar); override; stdcall; // Stub method; empty. // END Virtual Method implementation property Volume: Double read FVolume; property ID: Integer read FID; property Label: String read FLabel; end; I would have half expected using stdcall alone to work, but something is messing up, not sure what, perhaps something to do with the ECX register being used? Help would be greatly appreciated. Edit 2010-04-19 17:42 Could it be that the ECX register needs to be preserved on entry and restored once the function exits? Is the this pointer required by C++? I'm probably just reaching at the moment based on some intense Google searches. I found something related, but it seems to be dealing with the reverse of this issue.

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• Referencing ASP.net textbox data in JavaScripts

  - by GoldenEarring

  I'm interested in making an interactive 3D pie chart using JavaScript and ASP.net controls for a webpage. Essentially, I want to make an interactive version of the chart here: https://google-developers.appspot.com/chart/interactive/docs/gallery/piechart#3D I want to have 5 ASP.net textboxes where the user enters data and then submits it, and the chart adjusts according to what the user enters. I understand using ASP.net controls with JS is probably not the most effective way to go about it, but I would really appreciate if someone could share how doing this would be possible. I really don't know where to begin. Thanks for any help! <%@ Page Language="C#" %> <!DOCTYPE html> <script runat="server"> void btn1_Click(object sender, EventArgs e) { double s = 0.0; double b = 0; double g = 0.0f; double c = 0.0f; double h = 0.0f; s = double.Parse(txtWork.Text); b = double.Parse(txtEat.Text); g = double.Parse(txtCommute.Text); c = double.Parse(txtWatchTV.Text); h = double.Parse(txtSleep.Text); double total = s + b + g + c + h; if (total != 24) { lblError.Text = "Warning! A day has 24 hours"; } if (total == 24) { lblError.Text = string.Empty; } } </script> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> <script type="text/javascript" src="https://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("visualization", "1", { packages: ["corechart"] }); google.setOnLoadCallback(drawChart); function drawChart() { var data = google.visualization.arrayToDataTable([ ['Task', 'Hours per Day'], ['Work', 11], ['Eat', 2], ['Commute', 2], ['Watch TV', 2], ['Sleep', 7] ]); var options = { title: 'My Daily Activities', is3D: true, }; var chart = new google.visualization.PieChart(document.getElementById('piechart_3d')); chart.draw(data, options); } var data = new google.visualization.DataTable(); var txtWork = document.getElementById('<%=txtWork.ClientID%>') txtEat = document.getElementById('<%=txtEat.ClientID%>') txtCommute = document.getElementById('<%=txtCommute.ClientID%>') txtWatchTV = document.getElementById('<%=txtWatchTV.ClientID%>') txtSleep = document.getElementById('<%=txtSleep.ClientID%>'); var workvalue = parseInt(txtWork, 10) var eatvalue = parseInt(txtEat, 10) var commutevalue = parseInt(txtCommute, 10) var watchtvvalue = parseInt(txtWatchTV, 10) var sleepvalue = parseInt(txtSleep, 10) // Declare columns data.addColumn('string', 'Task'); data.addColumn('Number', 'Hours per day'); // Add data. data.addRows([ ['Work', workvalue], ['Eat', eatvalue], ['Commute', commutevalue], ['Watch TV', watchtvvalue], ['Sleep', sleepvalue], ]); </script> </head> <body> <form id="form1" runat="server"> <div id="piechart_3d" style="width: 900px; height: 500px;"> </div> <asp:Label ID="lblError" runat="server" Font-Size="X-Large" Font-Bold="true" /> <table> <tr> <td>Work:</td> <td><asp:TextBox ID="txtWork" Text="11" runat="server" /></td> </tr> <tr> <td>Eat:</td> <td><asp:TextBox ID="txtEat" text="2" runat="server" /></td> </tr> <tr> <td>Commute:</td> <td><asp:TextBox ID="txtCommute" Text="2" runat="server" /></td> </tr> <tr> <td>Watch TV:</td> <td><asp:TextBox ID="txtWatchTV" Text="2" runat="server" /></td> </tr> <tr> <td>Sleep:</td> <td><asp:TextBox ID="txtSleep" Text="7" runat="server" /></td> </tr> </table> <br /> <br /> <asp:Button ID="btn1" text="Draw 3D PieChart" runat="server" OnClick="btn1_Click" /> </form> </body> </html>

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• [SOLVED] BitmapFactory.decodeStream returning null when options are set.

  - by Robert Foss

  Hi! I'm having issues with BitmapFactory.decodeStream(inputStream). When using it without options, it will return an image. But when I use it with options as in .decodeStream(inputStream, null, options) it never returns Bitmaps. What I'm trying to do is to downsample a Bitmap before I actually load it to save memory. I've read some good guides, but none using .decodeStream. Here httpIM:NOT//nornalbion.SPAMcom/blog/?p=143 httpIM:NOT//kfb-android.blogspot.SPAMcom/2009/04/image-processing-in-android.html WORKS JUST FINE URL url = new URL(sUrl); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); InputStream is = connection.getInputStream(); Bitmap img = BitmapFactory.decodeStream(is, null, options); DOESNT WORK InputStream is = connection.getInputStream(); Bitmap img = BitmapFactory.decodeStream(is, null, options); InputStream is = connection.getInputStream(); Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeStream(is, null, options); Boolean scaleByHeight = Math.abs(options.outHeight - TARGET_HEIGHT) >= Math.abs(options.outWidth - TARGET_WIDTH); if(options.outHeight * options.outWidth * 2 >= 200*100*2){ // Load, scaling to smallest power of 2 that'll get it <= desired dimensions double sampleSize = scaleByHeight ? options.outHeight / TARGET_HEIGHT : options.outWidth / TARGET_WIDTH; options.inSampleSize = (int)Math.pow(2d, Math.floor( Math.log(sampleSize)/Math.log(2d))); } // Do the actual decoding options.inJustDecodeBounds = false; Bitmap img = BitmapFactory.decodeStream(is, null, options);

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• BitmapFactory.decodeStream returning null when options are set.

  - by Robert Foss

  Hi! I'm having issues with BitmapFactory.decodeStream(). When using it without options, it will return an image. But when I use it with options as in .decodeStream(inputStream, null, options) it never returns Bitmaps. What I'm trying to do is to downsample a Bitmap before I actually load it to save memory. I've read some good guides, but none using .decodeStream. Here httpIM:NOT//nornalbion.SPAMcom/blog/?p=143 httpIM:NOT//kfb-android.blogspot.SPAMcom/2009/04/image-processing-in-android.html WORKS JUST FINE InputStream is = connection.getInputStream(); Bitmap img = BitmapFactory.decodeStream(is, null, options); DOESNT WORK InputStream is = connection.getInputStream(); Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeStream(is, null, options); Boolean scaleByHeight = Math.abs(options.outHeight - TARGET_HEIGHT) >= Math.abs(options.outWidth - TARGET_WIDTH); if(options.outHeight * options.outWidth * 2 >= 200*100*2){ // Load, scaling to smallest power of 2 that'll get it <= desired dimensions double sampleSize = scaleByHeight ? options.outHeight / TARGET_HEIGHT : options.outWidth / TARGET_WIDTH; options.inSampleSize = (int)Math.pow(2d, Math.floor( Math.log(sampleSize)/Math.log(2d))); System.out.println("Samplesize: " + options.inSampleSize); } // Do the actual decoding options.inJustDecodeBounds = false; //options.inTempStorage = new byte[IMG_BUFFER_LEN]; Bitmap img = BitmapFactory.decodeStream(is, null, options);

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• Drawing Color Spectrum with Waveform

  - by TheDarkIn1978

  i've come across this ActionScript sample, which demonstrates drawing of the color spectrum, one line at a time via a loop, using waveforms. however, the waveform location of each RGB channel create a color spectrum that is missing colors (pure yellow, cyan and magenta) and therefore the spectrum is incomplete. how can i remedy this problem so that the drawn color spectrum will exhibit all colors? // Loop through all of the pixels from '0' to the specified width. for(var i:int = 0; i < nWidth; i++) { // Calculate the color percentage based on the current pixel. nColorPercent = i / nWidth; // Calculate the radians of the angle to use for rotating color values. nRadians = (-360 * nColorPercent) * (Math.PI / 180); // Calculate the RGB channels based on the angle. nR = Math.cos(nRadians) * 127 + 128 << 16; nG = Math.cos(nRadians + 2 * Math.PI / 3) * 127 + 128 << 8; nB = Math.cos(nRadians + 4 * Math.PI / 3) * 127 + 128; // OR the individual color channels together. nColor = nR | nG | nB; }

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• Positioning SVG Elements

  - by Rob Wilkerson

  In the course of toying with SVG for the first time (using the Raphael library), I've run into a problem positioning dynamic elements on the canvas in such a way that they're completely contained within the canvas. What I'm trying to do is randomly position n words/short phrases. Since the text is variable, its position needs to be variable as well so what I'm doing is: Initially creating the text at point 0,0 with no opacity. Checking the width of the drawn text element using text.getBBox().width. Setting a new x coordinate as Math.random() * (canvas_width - ( text_width/2 ) - pad). Altering the x coordinate of the text to the newly set value (text.attr( 'x', x ) ). Setting the opacity attribute of the text to 1. I'll be the first to admit that my math acumen is limited, but this seems pretty straightforward. Somehow, I still end up with text running off beyond the right edge of my canvas. For simplicity above, I removed the bit that also sets a minimum x value by adding it to the Math.random() result. It is there, though, and I see the same problem on the leading edge of the canvas. My understanding (such as it is), is that the Math.random() bits would generate a number between 0 and 1 which could then be multiplied by some number (in my case, the canvas width - half of the text width - some arbitrary padding) to get the outer bound. I'm dividing the width of the text in half because its position on the grid is set at its center. I hope I've just been staring at this for too long, but is my math that rusty or am I misunderstanding something about the behavior of Math.random(), SVG, text or anything else that's under the hood of this solution?

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• C# Why can't I find Sum() of this HashSet. says "Arithmetic operation resulted in an overflow."

  - by user2332665

  I was trying to solve this problem projecteuler,problem125 this is my solution in python(just for understanding the logic) import math lim=10**8 found=set() for start in xrange(1,int(math.sqrt(lim))): sos = start*start for i in xrange(start+1,int(math.sqrt(lim))): sos += (i*i) if sos >= lim: break s=str(int(sos)) if s==s[::-1]: found.add(sos) print sum(found) the same code I wrote in C# is as follows using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { public static bool isPalindrome(string s) { string temp = ""; for (int i=s.Length-1;i>=0;i-=1){temp+=s[i];} return (temp == s); } static void Main(string[] args) { int lim = Convert.ToInt32(Math.Pow(10,8)); var found = new HashSet<int>(); for (int start = 1; start < Math.Sqrt(lim); start += 1) { int s = start *start; for (int i = start + 1; start < Math.Sqrt(lim); i += 1) { s += i * i; if (s > lim) { break; } if (isPalindrome(s.ToString())) { found.Add(s); } } } Console.WriteLine(found.Sum()); } } } the code debugs fine until it gives an exception at Console.WriteLine(found.Sum()); (line31). Why can't I find Sum() of the set found

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• Draw multiple circles in Google Maps

  - by snorpey

  Hi. I want to draw multiple circles on a map, using the Google Maps API anj jQuery. The following code works as long as the line with drawMapCircle() is commented out (The markers are positioned correctly). What's wrong with my code? $.getJSON( "ajax/show.php", function(data) { $.each(data.points, function(i, point) { map.addOverlay(new GMarker(new GLatLng(point.lat, point.lng))); drawMapCircle(point.lat, point.lng, 0.01, '#0066ff', 2, 0.8, '#0cf', 0.1); }); } ); function drawMapCircle(lat, lng, radius, strokeColor, strokeWidth, strokeOpacity, fillColor, fillOpacity) { var d2r = Math.PI / 180; var r2d = 180 / Math.PI; var Clat = radius * 0.014483; // statute miles into degrees latitude conversion var Clng = Clat/Math.cos(lat * d2r); var Cpoints = []; for (var i = 0; i < 33; i++) { var theta = Math.PI * (i / 16); Cy = lat + (Clat * Math.sin(theta)); Cx = lng + (Clng * Math.cos(theta)); var P = new GLatLng(Cy, Cx); Cpoints.push(P); } var polygon = new GPolygon(Cpoints, strokeColor, strokeWidth, strokeOpacity, fillColor, fillOpacity); map.addOverlay(polygon); }

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• Simple in-place discrete fourier transform ( DFT )

  - by Adam

  I'm writing a very simple in-place DFT. I am using the formula shown here: http://en.wikipedia.org/wiki/Discrete_Fourier_transform#Definition along with Euler's formula to avoid having to use a complex number class just for this. So far I have this: private void fft(double[] data) { double[] real = new double[256]; double[] imag = new double[256]; double pi_div_128 = -1 * Math.PI / 128; for (int k = 0; k < 256; k++) { for (int n = 0; n < 256; n++) { real[k] += data[k] * Math.Cos(pi_div_128 * k * n); imag[k] += data[k] * Math.Sin(pi_div_128 * k * n); } data[k] = Math.Sqrt(real[k] * real[k] + imag[k] * imag[k]); } } But the Math.Cos and Math.Sin terms eventually go both positive and negative, so as I'm adding those terms multiplied with data[k], they cancel out and I just get some obscenely small value. I see how it is happening, but I can't make sense of how my code is perhaps mis-representing the mathematics. Any help is appreciated. FYI, I do have to write my own, I realize I can get off-the shelf FFT's.

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• Creating/Maintaining a large project-agnostic code library

  - by bufferz

  In order to reduce repetition and streamline testing/debugging, I'm trying to find the best way to develop a group of libraries that many projects can utilize. I'd like to keep individual executable relatively small, and have shared libraries for math, database, collections, graphics, etc. that were previously scattered among several projects and in many cases duplicated (bad!). This library is to be in an SVN repo and several programmers will be working on it. This library will be in constant development along with the executables that utilize it. For example, I want a code file in ProjectA to look something like the following: using MyCompany.Math.2D; //static 2D math methods using MyCompany.Math.3D; //static #D math methods using MyCompany.Comms.SQL; //static methods for doing simple SQLDB I/O using MyCompany.Graphics.BitmapOperations; //static methods that play with bitmaps So in my ProjectA solution file in VisualStudio, in order to develop/debug the MyCompany library I have to add several projects (Math, Comms, Graphics). Things get pretty cluttered and Solution files get out of date quickly between programmer SVN commits. I'm just looking for a high level approach to maintaining a large, shared code base in an SCN repository. I am fully willing to radically redesign my approach. I'm looking for that warm fuzzy feeling you get when you're design approach is spot on and development is fluid and natural. And ideas? Thanks!!

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• Difficulty with projectile's tracking code

  - by RCIX

  I wrote some code for a projectile class in my game that makes it track targets if it can: if (_target != null && !_target.IsDead) { Vector2 currentDirectionVector = this.Body.LinearVelocity; currentDirectionVector.Normalize(); float currentDirection = (float)Math.Atan2(currentDirectionVector.Y, currentDirectionVector.X); Vector2 targetDirectionVector = this._target.Position - this.Position; targetDirectionVector.Normalize(); float targetDirection = (float)Math.Atan2(targetDirectionVector.Y, targetDirectionVector.X); float targetDirectionDelta = targetDirection - currentDirection; if (MathFunctions.IsInRange(targetDirectionDelta, -(Info.TrackingRate * deltaTime), Info.TrackingRate * deltaTime)) { Body.LinearVelocity = targetDirectionVector * Info.FiringVelocity; } else if (targetDirectionDelta > 0) { float newDirection = currentDirection + Info.TrackingRate * deltaTime; Body.LinearVelocity = new Vector2( (float)Math.Cos(newDirection), (float)Math.Sin(newDirection)) * Info.FiringVelocity; } else if (targetDirectionDelta < 0) { float newDirection = currentDirection - Info.TrackingRate * deltaTime; Body.LinearVelocity = new Vector2( (float)Math.Cos(newDirection), (float)Math.Sin(newDirection)) * Info.FiringVelocity; } } This works sometimes, but depending on the relative angle to the target projectiles turn away from the target instead. I'm stumped; can someone point out the flaw in my code?

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• Drawing straight lines in JavaScript

  - by Shawn31313

  I'm just trying to draw a line with JavaScript. I would like it to be like this: http://deepliquid.com/projects/blog/arrows2.html My version: http://jsfiddle.net/shawn31313/qsWML/5/show Doesn't work too well and I don't know how to get it too work. It must be an issue in my JavaScript. This my code: $(document).ready(function() { var dragStatus = 2, getPos, giveRandomID; $(document).mousedown(function(event) { dragStatus = 0; getPos = { top: event.clientY, left: event.clientX }; giveRandomID = Math.floor(Math.random() * 99999); }); $(document).mousemove(function() { var line = $('#line' + giveRandomID); if (dragStatus == 0) { $('body').append("<div id='line" + giveRandomID + "' style='position:absolute;top:" + getPos.top + "px;left:" + getPos.left + "px;background:black;width:2px;height:5px'></div>"); dragStatus = 1; } if (dragStatus == 1) { if (event.clientX > getPos.left) { line.css({ left: getPos.left, width: event.clientX - getPos.left }); } else { line.css({ left: event.clientX, width: getPos.left - event.clientX }); } if (event.clientY > getPos.top) { line.css({ top: getPos.top - Math.abs((event.clientY - getPos.top) * 2), '-webkit-transform': 'rotate(' + (event.clientY - getPos.top) + 'deg)' }); } else { line.css({ top: getPos.top + Math.abs((getPos.top - event.clientY) * 2), '-webkit-transform': 'rotate(' + (getPos.top - event.clientY) + 'deg)' }); } //for DEG "-" Top-Math.abs(DEG*2) for Deg "+" Top+(DEG*2) } }); $(document).mouseup(function() { dragStatus = 2; }); });? Thanks for any help fixing this. Mainly an issue with the math, just don't know how I can fix this.

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• Best way to implement a data structure in PHP ?

  - by Double Gras

  Hi, I want to use some kind of data structure in PHP (5.2), mainly in order to not pollute the global namespace. I think about two approaches, using an array or a class. Could you tell me which approach is better ? Thanks $SQL_PARAMETERS = array ( 'server' => '127.0.0.1', 'login' => 'root'); class SqlParameters { const SERVER = '127.0.0.1'; const LOGIN = 'root'; } echo $SQL_PARAMETERS['server']; echo SqlParameters::SERVER;

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• SQLiteDataAdapter Fill exception

  - by Lirik

  I'm trying to use the OleDb CSV parser to load some data from a CSV file and insert it into a SQLite database, but I get an exception with the OleDbAdapter.Fill method and it's frustrating: An unhandled exception of type 'System.Data.ConstraintException' occurred in System.Data.dll Additional information: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints. Here is the source code: public void InsertData(String csvFileName, String tableName) { String dir = Path.GetDirectoryName(csvFileName); String name = Path.GetFileName(csvFileName); using (OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + dir + @";Extended Properties=""Text;HDR=No;FMT=Delimited""")) { conn.Open(); using (OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM " + name, conn)) { QuoteDataSet ds = new QuoteDataSet(); adapter.Fill(ds, tableName); // <-- Exception here InsertData(ds, tableName); // <-- Inserts the data into the my SQLite db } } } class Program { static void Main(string[] args) { SQLiteDatabase target = new SQLiteDatabase(); string csvFileName = "D:\\Innovations\\Finch\\dev\\DataFeed\\YahooTagsInfo.csv"; string tableName = "Tags"; target.InsertData(csvFileName, tableName); Console.ReadKey(); } } The "YahooTagsInfo.csv" file looks like this: tagId,tagName,description,colName,dataType,realTime 1,s,Symbol,symbol,VARCHAR,FALSE 2,c8,After Hours Change,afterhours,DOUBLE,TRUE 3,g3,Annualized Gain,annualizedGain,DOUBLE,FALSE 4,a,Ask,ask,DOUBLE,FALSE 5,a5,Ask Size,askSize,DOUBLE,FALSE 6,a2,Average Daily Volume,avgDailyVolume,DOUBLE,FALSE 7,b,Bid,bid,DOUBLE,FALSE 8,b6,Bid Size,bidSize,DOUBLE,FALSE 9,b4,Book Value,bookValue,DOUBLE,FALSE I've tried the following: Removing the first line in the CSV file so it doesn't confuse it for real data. Changing the TRUE/FALSE realTime flag to 1/0. I've tried 1 and 2 together (i.e. removed the first line and changed the flag). None of these things helped... One constraint is that the tagId is supposed to be unique. Here is what the table look like in design view: Can anybody help me figure out what is the problem here? Update: I changed the HDR property from HDR=No to HDR=Yes and now it doesn't give me an exception: OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + dir + @";Extended Properties=""Text;HDR=Yes;FMT=Delimited"""); I assumed that if HDR=No and I removed the header (i.e. first line), then it should work... strangely it didn't work. In any case, now I'm no longer getting the exception. The new problem is here: public void InsertData(QuoteDataSet data, String tableName) { using (SQLiteConnection conn = new SQLiteConnection(_connectionString)) { conn.Open(); using (SQLiteDataAdapter sqliteAdapter = new SQLiteDataAdapter("SELECT * FROM " + tableName, conn)) { Console.WriteLine("Num rows updated is " + sqliteAdapter.Update(data, tableName)); } } } Now the Num rows updated is 0... any hints?

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• XSL Template outputting massive chunk of text, rather than HTML. But only on one section

  - by Throlkim

  I'm having a slightly odd situation with an XSL template. Most of it outputs fine, but a certain for-each loop is causing me problems. Here's the XML: <area> <feature type="Hall"> <Heading><![CDATA[Hall]]></Heading> <Para><![CDATA[Communal gardens, pathway leading to PVCu double glazed communal front door to]]></Para> </feature> <feature type="Entrance Hall"> <Heading><![CDATA[Communal Entrance Hall]]></Heading> <Para><![CDATA[Plain ceiling, centre light fitting, fire door through to inner hallway, wood and glazed panelled front door to]]></Para> </feature> <feature type="Inner Hall"> <Heading><![CDATA[Inner Hall]]></Heading> <Para><![CDATA[Plain ceiling with pendant light fitting and covings, security telephone, airing cupboard housing gas boiler serving domestic hot water and central heating, telephone point, storage cupboard housing gas and electric meters, wooden panelled doors off to all rooms.]]></Para> </feature> <feature type="Lounge (Reception)" width="3.05" length="4.57" units="metre"> <Heading><![CDATA[Lounge (Reception)]]></Heading> <Para><![CDATA[15' 6" x 10' 7" (4.72m x 3.23m) Window to the side and rear elevation, papered ceiling with pendant light fitting and covings, two double panelled radiators, power points, wall mounted security entry phone, TV aerial point.]]></Para> </feature> <feature type="Kitchen" width="3.05" length="3.66" units="metre"> <Heading><![CDATA[Kitchen]]></Heading> <Para><![CDATA[12' x 10' (3.66m x 3.05m) Double glazed window to the rear elevation, textured ceiling with strip lighting, range of base and wall units in Beech with brushed aluminium handles, co-ordinated working surfaces with inset stainless steel sink with mixer taps over, co-ordinated tiled splashbacks, gas and electric cooker points, large storage cupboard with shelving, power points.]]></Para> </feature> <feature type="Entrance Porch"> <Heading><![CDATA[Balcony]]></Heading> <Para><![CDATA[Views across the communal South facing garden, wrought iron balustrade.]]></Para> </feature> <feature type="Bedroom" width="3.35" length="3.96" units="metre"> <Heading><![CDATA[Bedroom One]]></Heading> <Para><![CDATA[13' 6" x 11' 5" (4.11m x 3.48m) Double glazed windows to the front and side elevations, papered ceiling with pendant light fittings and covings, single panelled radiator, power points, telephone point, security entry phone.]]></Para> </feature> <feature type="Bedroom" width="3.05" length="3.35" units="metre"> <Heading><![CDATA[Bedroom Two]]></Heading> <Para><![CDATA[11' 4" x 10' 1" (3.45m x 3.07m) Double glazed window to the front elevation, plain ceiling with centre light fitting and covings, power points.]]></Para> </feature> <feature type="bathroom"> <Heading><![CDATA[Bathroom]]></Heading> <Para><![CDATA[Obscure double glazed window to the rear elevation, textured ceiling with centre light fitting and extractor fan, suite in white comprising of low level WC, wall mounted wash hand basin and walk in shower housing 'Triton T80' electric shower, co-ordinated tiled splashbacks.]]></Para> </feature> </area> And here's the section of my template that processes it: <xsl:for-each select="area"> <li> <xsl:for-each select="feature"> <li> <h5> <xsl:value-of select="Heading"/> </h5> <xsl:value-of select="Para"/> </li> </xsl:for-each> </li> </xsl:for-each> And here's the output: Hall Communal gardens, pathway leading to PVCu double glazed communal front door to Communal Entrance Hall Plain ceiling, centre light fitting, fire door through to inner hallway, wood and glazed panelled front door to Inner Hall Plain ceiling with pendant light fitting and covings, security telephone, airing cupboard housing gas boiler serving domestic hot water and central heating, telephone point, storage cupboard housing gas and electric meters, wooden panelled doors off to all rooms. Lounge (Reception) 15' 6" x 10' 7" (4.72m x 3.23m) Window to the side and rear elevation, papered ceiling with pendant light fitting and covings, two double panelled radiators, power points, wall mounted security entry phone, TV aerial point. Kitchen 12' x 10' (3.66m x 3.05m) Double glazed window to the rear elevation, textured ceiling with strip lighting, range of base and wall units in Beech with brushed aluminium handles, co-ordinated working surfaces with inset stainless steel sink with mixer taps over, co-ordinated tiled splashbacks, gas and electric cooker points, large storage cupboard with shelving, power points. Balcony Views across the communal South facing garden, wrought iron balustrade. Bedroom One 13' 6" x 11' 5" (4.11m x 3.48m) Double glazed windows to the front and side elevations, papered ceiling with pendant light fittings and covings, single panelled radiator, power points, telephone point, security entry phone. Bedroom Two 11' 4" x 10' 1" (3.45m x 3.07m) Double glazed window to the front elevation, plain ceiling with centre light fitting and covings, power points. Bathroom Obscure double glazed window to the rear elevation, textured ceiling with centre light fitting and extractor fan, suite in white comprising of low level WC, wall mounted wash hand basin and walk in shower housing 'Triton T80' electric shower, co-ordinated tiled splashbacks. For reference, here's the entire XSLT: http://pastie.org/private/eq4gjvqoc1amg9ynyf6wzg The rest of it all outputs fine - what am I missing from the above section?

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• Trying to change variables in a singleton using a method

  - by Johnny Cox

  I am trying to use a singleton to store variables that will be used across multiple view controllers. I need to be able to get the variables and also set them. How do I call a method in a singleton to change the variables stored in the singleton. total+=1079; [var setTotal:total]; where var is a static Singleton *var = nil; I need to update the total and send to the setTotal method inside the singleton. But when I do this the setTotal method never gets accessed. The get methods work but the setTotal method does not. Please let me know what should. Below is some of my source code // // Singleton.m // Rolo // // Created by on 6/28/12. // Copyright (c) 2012 Johnny Cox. All rights reserved. // #import "Singleton.h" @implementation Singleton @synthesize total,tax,final; #pragma mark Singleton Methods + (Singleton *)sharedManager { static Singleton *sharedInstance = nil; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ sharedInstance = [[Singleton alloc] init]; // Do any other initialisation stuff here }); return sharedInstance; } +(void) setTotal:(double) tot { Singleton *shared = [Singleton sharedManager]; shared.total = tot; NSLog(@"hello"); } +(double) getTotal { Singleton *shared = [Singleton sharedManager]; NSLog(@"%f",shared.total); return shared.total; } +(double) getTax { Singleton *shared = [Singleton sharedManager]; NSLog(@"%f",shared.tax); return shared.tax; } @end // // Singleton.h // Rolo // // Created by on 6/28/12. // Copyright (c) 2012 Johnny Cox. All rights reserved. // #import <Foundation/Foundation.h> @interface Singleton : NSObject @property (nonatomic, assign) double total; @property (nonatomic, assign) double tax; @property (nonatomic, assign) double final; + (id)sharedManager; +(double) getTotal; +(void) setTotal; +(double) getTax; @end

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• Scala Array constructor?

  - by Lukasz Lew

  scala> val a = Array [Double] (10) a: Array[Double] = Array(10.0) scala> val a = new Array [Double] (10) a: Array[Double] = Array(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0) Why these two expressions have different semantics?

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• Java: CSV file read & write.

  - by battousai622

  Im reading in 2 csv file: store_inventory & new_acquisitions... I want to be able to compare the store_inventory csv file with new_acquisitions. 1) If the item names match just update the quantity in store_inventory. 2) If new_acquisitions has a new item that does not exist in store_inventory, then add it to the store_inventory. Heres what i have so far but its not very good. I added comments where i need to add taks 1) & 2). Any advice or code would be great, thanks. File new_acq = new File("/src/test/new_acquisitions.csv"); Scanner acq_scan = null; try { acq_scan = new Scanner(new_acq); } catch (FileNotFoundException ex) { Logger.getLogger(mainpage.class.getName()).log(Level.SEVERE, null, ex); } String itemName; int quantity; Double cost; Double price; File store_inv = new File("/src/test/store_inventory.csv"); Scanner invscan = null; try { invscan = new Scanner(store_inv); } catch (FileNotFoundException ex) { Logger.getLogger(mainpage.class.getName()).log(Level.SEVERE, null, ex); } String itemNameInv; int quantityInv; Double costInv; Double priceInv; while (acq_scan.hasNext()) { String line = acq_scan.nextLine(); if (line.charAt(0) == '#') { continue; } String[] split = line.split(","); itemName = split[0]; quantity = Integer.parseInt(split[1]); cost = Double.parseDouble(split[2]); price = Double.parseDouble(split[3]); while(invscan.hasNext()) { String line2 = invscan.nextLine(); if (line2.charAt(0) == '#') { continue; } String[] split2 = line2.split(","); itemNameInv = split2[0]; quantityInv = Integer.parseInt(split2[1]); costInv = Double.parseDouble(split2[2]); priceInv = Double.parseDouble(split2[3]); if(itemName == itemNameInv) { //update quantity } } //add new entry into csv file } Thanks again for any help. =]

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