I am making a pong game and this is what i got so far

Code:
#include <allegro.h>

int x = 5;
int y = 0;
int counter;
int down = 0, up = 0;
int x2 = 615;
int y2 = 0;
int counter2;
int down2 = 0, up2 = 0;
int play1scor = 0;
int play2scor = 0;
int ballx = 300, bally = 190;

void update_counter()
{
     counter++;
}
END_OF_FUNCTION(update_counter);

void update_counter2()
{
     counter2++;
}
END_OF_FUNCTION(update_counter2);

int main()
{
   allegro_init();
   install_keyboard();
   
   LOCK_VARIABLE(counter);
   LOCK_FUNCTION(update_counter);
   install_int_ex( update_counter, BPS_TO_TIMER(60));
   
   LOCK_VARIABLE(counter2);
   LOCK_FUNCTION(update_counter2);
   install_int_ex( update_counter2, BPS_TO_TIMER(60));

   set_color_depth(32);
   set_gfx_mode(GFX_AUTODETECT_FULLSCREEN, 640, 480, 0, 0);

   BITMAP *bar = load_bitmap( "sprite/bar.bmp", NULL );
   BITMAP *logo = load_bitmap( "sprite/logo.bmp", NULL );
   BITMAP *ball = load_bitmap( "sprite/ball.bmp", NULL );
   
   while ( !key[KEY_ESC] )
   {
   
        while ( counter > 0 ) 
        { 
            if (down)  y-=7;
            if (up) y+=7;
            counter--; 
        }
        if ( y > 0 && key[KEY_UP])
            down = 1;
        else 
            down = 0; 
        if ( y < 375 && key[KEY_DOWN])
            up = 1;
        else 
            up = 0; 
        while ( counter2 > 0 ) 
        { 
            if (down2)  y2-=7;
            if (up2) y2+=7;
            counter2--; 
        }
        if ( y2 > 0 && key[KEY_A])
            down2 = 1;
        else 
            down2 = 0; 
        if ( y2 < 375 && key[KEY_Z])
            up2 = 1;
        else 
            up2 = 0;
 
        vsync();
        clear_to_color (screen, 0);
        draw_sprite ( screen, bar, x, y );
        draw_sprite ( screen, bar, x2, y2 );
        draw_sprite ( screen, logo, 245, 200 );
        draw_sprite ( screen, ball, ballx, bally );
        
   }


   destroy_bitmap(bar);
   destroy_bitmap(logo);
   allegro_exit();
   return 0;
}
END_OF_MAIN();
how do i make the ball move and... you know... do what the pong ball does?

thanks