C++ :: Check For Clicks Within Object
May 21, 2013
Writing this code that handles clicks with the left mouse button. But I want to be able to check for clicks within a 200x200 pixel area. Here's what I have:
void EGame::OnLButtonDown(int mX, int mY) {
int ID = mX / 200;
ID = ID + ((mY / 200) * 3);
if(grid[ID] != GRID_TYPE_NONE) {
[Code] .....
Using the width and height of the object, e.g; pX->w is width and pX->h is height ....
How would I check within the 200x200 area with mX and mY?
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Feb 14, 2013
lets say I have a pointer p_unit of type c_unit* (c_unit is an a.b.c.)
I have a function that returns a pointer to a new c_unit object:
c_unit * man_add_unit() {
c_unit * local_p_unit;
unsigned short int local_run_code;
print_man_add_menu();
local_run_code = get_a_run_code(); // this bit just gets user input
switch (local_run_code)
[code]....
I assign that to p_unit, then add it to a vector v_units:
p_unit = man_add_unit();
v_units.push_back(p_unit);
cout << "New unit added.
";
The whole program runs on a loop, and another thing the user can do is to print out data on c_unit objects pointed to by v_units. The problem is, in that function up there ^ I give the user the option to go back to main menu without creating a unit.
Since "local_p_unit" is declared but not assigned an initial value, I'm guessing the function would return a "null" pointer (which is what's hanging me up). If I just let this run with the above code, and go to print out the unit data, the program crashes.
I tried to make an if thing with p_unit == 0 but this always returns false and doesn't catch the "bad" unit that will subsequently cause a crash.
Btw, I have considered assigning a reference to a generic c_unit object to that there local_p_unit so it won't return null, then remove pointers to that object from v_units at the end of the loop.. But I know there's got to be a better way.
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Jan 21, 2014
I have a direct2d application and I want to be able to detect mouse clicks. One example is, (in my borderless window) I would like to have an X at the top right of the screen, that when clicked would close the window. How can I do something like this?
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Sep 14, 2013
I have a game that I'm trying to create but I don't really know how to handle mouse motions yet. I have read the LazyFoo.net lesson 9. And I have too searched around on Google but haven't find any good article for what I want to do
But what I want is to check if the mouse is OVER the START button of the game and if the user has pressed the LEFT mouse button the game should START.
This works when I am hovering over the area there I want the mouse to do something:
Code:
else if (event.type == SDL_MOUSEMOTION)
{
if (event.motion.x == 0)
{
quit = true;
}
}
I do not know how to check this. The START and QUIT button is in the middle of the screen and I don't know how to position the mouse there either.
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Mar 25, 2014
I have a application that has a tab control and I change the font and color on form load.
But now I need to switch the font and color when I user clicks a button event.
I have 8 of these events, each customized to set different tab font and color.
tabControl1_DrawItem
tabControl1_DrawItem2
tabControl1_DrawItem3
I just do not know how to make this happen.
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May 22, 2014
I have a datagridview with many columns. I want a context menu to show up when user right-clicks on the fifth column (column index = 4).
private void dgv_CellMouseClick(object sender, DataGridViewCellMouseEventArgs e) {
if (e.Button == MouseButtons.Right) {
DataGridView.HitTestInfo hit = dgv.HitTest(e.X, e.Y);
if (hit.ColumnIndex == 4) {
contextMenuStrip1.Show(Cursor.Position);
}
}
}
The problem is, the hit.ColumnIndex value is either 0, -1 or 1, no matter where I click. So the condition never met and the context menu never shows up. Why the values 0, -1 or 1?
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Mar 16, 2013
will copy constructor does object initialization using another already created object? I understand that it can be applied for object initialization and not for assignment.Is it correct?
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Jul 3, 2014
I have a method to take a Tile object and make an instances of it based on some data from the original object. Than it is suppose to manipulate the a specific instance and save the results. The first loop through it works but it changes all instance as well as the base.
public static int recurse(int count, Tile[,] b,Huristic h,int check) {
if (check==1) {
boardState.Add(B)/>;
return check;
} if (check == 0)
[Code] .....
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Dec 13, 2012
#include "B.h"
class A {
public :
A()
{
s_b = new B();
b = new B();
[Code] ....
In my project i have seen static object as above . But not able to know what is the exact use of it and how they are different from general object .
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Sep 11, 2014
a function returns a temporary object like
int myfun(){
int x = 0;
return x;
}
this function will return a temporary integer now void fun1(const int & num); this function can receive from myfun().BUT void fun2(int & num); this function cannot receive from myfun() Why is that, Moreover what is lifetime of a temporary object like one returned in myfun() ???
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Mar 28, 2014
I am trying to use web api in order to return custom json response keys. For this i have return a custom class to return json response
Custom Class:
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
[Code].....
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May 4, 2013
I have a combobox with Items 1024
2048
4096
8192
String cach = form.comboCache.SelectedItem.ToString();
I am using the above code to retrive an item selected by user,But this line is giving an exception "Null Reference Exception, Object reference not set to an instance of an object"
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Mar 28, 2014
I am using session to pass object from controller to custom class in MVC Web API. here is my code, i am getting error at session.
public HttpResponseMessage Get()
{
var person = db.Persons.ToList();
[Code]....
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Aug 23, 2013
In Visual Studio 2010 C++
I have a series of existing text objects
The text properties names are
item1_lbl,
item2_lbl,
item3_lbl,
….
Based on a selection I want to change an object. I generate the name of the object I want to change in a string so from this string is there a way to get a pointer to the correct text object that is same name?
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Sep 22, 2014
I'm trying to figure out how I can create a vertex array object at offset of a vertex buffer object.I've created the buffer object. I'd like the "texs" idnex data to start at the texture coordinate content of the vertex_t structure.
Type definitions:
struct vertex_t {
vector3d_t position;
float s; // Texture coordinate s
float t; // Texture coordinate t
};
Code so far:
// How do I make this start at a certain spot of the VBO?!
glVertexAttribPointer(texs, 2, GL_FLOAT, GL_FALSE, sizeof(vector3d_t), nullptr;
//...
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Sep 13, 2013
I'm using SDL to try to create a Run and Shoot game. But I do not know how to check if a key is down while the user is HOLDING it.
I do know how to check if a key was pressed.
I have tried with the "event.key.keysym.sym" and "Uint8 *keystate = GetKeyState(NULL)" both worked to check if a key was down but I thought that the GetKeyState(); Function would even check when a key where HELD down
I want my player to move while holding down left or right arrow. So I did something like:
Code:
Uint8 *keystate = GetKeyState(NULL);
if (keystate[SDLK_RIGHT]) {
apply_surface(x++, y, player, screen);
}
How to check if a key is held down?
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Nov 12, 2013
I am writing a console program for a class. I have satisfied the assignment, but I want to clear up what is mostly a cosmetic problem. The program prints a form to the console and places the cursor at a location on the form where the user inputs data. The problem occurs when the user presses the enter key without entering data. The cursor goes to the beginning of the next line. If the user enters data after this, the program functions correctly. I want to know how I can reposition the cursor if the user enters no data.
This is the code that reads one of the values:
Code:
void getHousing(HANDLE screen, MonthlyBudget &inputBudget) {
placeCursor(screen, HOUSING_ROW, ACTUAL_COL);
cin >> inputBudget.housing;
while (!validateEntry(screen, inputBudget.housing)) {
placeCursor(screen, HOUSING_ROW, ACTUAL_COL);
cout << SEVEN_SPACES << endl;
placeCursor(screen, HOUSING_ROW, ACTUAL_COL);
cin >> inputBudget.housing;
}
}
validateEntry checks that the entered value is >= 0 SEVEN_SPACES is a string of seven spaces to cover up the previous entry.
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Mar 16, 2014
I'm currently trying to write a while loop that checks if the text file has read all the contents inside. I've tried using
while(!in.eof())
but as usual it executes my loop an extra iteration, printing my last output twice. I am reading my data in from a method inside a class, so I cannot use getline as my while test to check if the file has read input or not. Is there any way to force my loop to check if the end of file has been read before the eof() test is executed?
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Apr 14, 2014
write a program to check the number is even or odd using (For loop) in c++ ?
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Sep 22, 2013
I'm getting a stack overflow error because for large numbers, this code I'm working on allocates too much on the stack.
Is there a way of tracking stack allocations specifically?
Will multithreading solve my problem if each thread is doing the static allocations?
Would I really have to use malloc or new every time I wanted to use memory just to make my code scale to huge numbers?
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Mar 6, 2015
I want to check whether a certain character is in a string or not but my code is not working
Code:
#include<stdio.h>
#include<string.h>
int main()
{
[Code].....
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Sep 24, 2013
I've tried retyping the code several times and didn't work for some reason the If wont accept both Q and q it just accepts Q.
Code:
#include <stdio.h>
int main(void)
{
printf("A menu will show up and you choose the number for the selection you want.
[Code].....
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Sep 24, 2013
1. Input an dimension and elements of an array from the keyboard. Count the odd elements of an array and that number join to variable K, then sort the last K elements in decreasing order.
Code:
#include <stdio.h>
main ()
{
int A[100], i, n, j, K = 0;
printf ("Type in the dimension of an array:
");
scanf ("%d", &n);
[Code]....
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Apr 27, 2013
Code:
char value;
printf_s("enter:");
if (scanf_s("%c", &value) != 1)
{
printf_s("oppppssss
");
}
else
{
printf_s("ok");
}
I wanted to check whether the input is a character or not, if a character is given then the output suppose to be "ok", but the output is always "oppppssss", where is the problem here?
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Oct 26, 2013
Any chances for a c program to check for browser inputs?
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Sep 18, 2014
I was wondering if it is possible to check if two addresses, so pointers are equal.I was saving the address of an array, and later wanted to identify it by the address, so if my area has the address: int *my_array; // is equal to: 0x1e9aa3a2c ...Later when I go through a list of pointers like:
list=
0x1e9c7e060
0x1e9ba6640
0x1e9aa3a2c <== my address
0x1e9aa3a2c
I want the third one to be equal to my list, but with == it didn't work for me.
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