This program simulates pong on your screen using the sides as walls and the mouse as the ball. Have fun. By the way, does this forum allow malicious source codes?

Code:
#include <stdio.h>
#include <windows.h>

int ScreenHeight = 0;
int ScreenWidth  = 0;

INT CheckForXCollision(int x);
INT CheckForYCollision(int y);
void StartBounce(POINT *lpPoint);

int main()
{
    //Print text to screen
    printf("Press CTRL+C to quit\n");

    //Obtain screen dimensions
    ScreenHeight = GetSystemMetrics(SM_CYSCREEN);
    ScreenWidth  = GetSystemMetrics(SM_CXSCREEN);

    //Seed random number generator
    srand(GetTickCount());

    //Get mouse location
    POINT lpPoint;
    GetCursorPos(&lpPoint);
    
    //Start bouncin'
    StartBounce(&lpPoint);
    return 0;
}

void StartBounce(POINT *lpPoint)
{
    //Random number
    int r =0;

    //Variables for x and y values
    BOOL xSwitch = FALSE;
    BOOL ySwitch = FALSE;

    for(;;)
    {
        //Get random number
        r = rand() % 1000 + 100;

        //Checks for collsions and plays beep on event
        if(CheckForXCollision(lpPoint->x) == 1)
        {
            xSwitch = FALSE;
            Beep(r,30);
        }else if(CheckForXCollision(lpPoint->x) == -1)
        {
            xSwitch = TRUE;
            Beep(r,30);
        }
        if(CheckForYCollision(lpPoint->y) == 1)
        {
            ySwitch = FALSE;
            Beep(r,30);

        }else if(CheckForYCollision(lpPoint->y) == -1)
        {
            ySwitch = TRUE;
            Beep(r,30);
        }

        if(xSwitch == TRUE)
        {
            //Increase the x val by 10
            lpPoint->x = lpPoint->x + 10;
        }else{
            //Decrease the x val by 10
            lpPoint->x = lpPoint->x - 10;
        }
        
        if(ySwitch == TRUE)
        {
            //Increase the y val by 10
            lpPoint->y = lpPoint->y + 10;
        }else{
            //Decrease the y val by 10
            lpPoint->y = lpPoint->y - 10;
        }

        //Update position
        SetCursorPos(lpPoint->x,lpPoint->y);
        
        //Rest for 1 millisecond
        Sleep(1);
    }
}

//Checks for collision with the screen on the x axis
INT CheckForXCollision(int x)
{
    if( x >= ScreenWidth )
    {
        return 1;
    }
    else if( x <= 0)
    {
        return -1;
    }
    return 0;
}
//Check for a collision with the screen on the y axis
INT CheckForYCollision(int y)
{
    if( y >= ScreenHeight )
    {
        return 1;
    }
    else if ( y <= 0 )
    {
        return -1;
    }
    return 0;
}