for(int j=0; j<NUMOBJ; j++)
{
    for(int k=(j+1); k<NUMOBJ; k++)
    {
        if(object[j].sprite->collision( object[k].sprite))
        {
            dx = abs(object[j].sprite->pos.x - object[k].sprite->pos.x);
            dy = abs(object[j].sprite->pos.y - object[k].sprite->pos.y);
            if(dx>dy)
            {
                object[j].sprite->pos.x -= object[j].sprite->vel.x;
                object[k].sprite->pos.x -= object[k].sprite->vel.x;
                 
                temp = object[j].sprite->vel.x;
                object[j].sprite->vel.x = object[k].sprite->vel.x;
                object[k].sprite->vel.x = temp;
            }
            else
            {
                object[j].sprite->pos.y -= object[j].sprite->vel.y;
                object[k].sprite->pos.y -= object[k].sprite->vel.y;

                temp = object[j].sprite->vel.y;
                object[j].sprite->vel.y = object[k].sprite->vel.y;
                object[k].sprite->vel.y = temp;
            }
        }
    }
}