即使使用引用，函数也不会更改 C++ 中的对象属性

Question

我正在尝试ball通过调用函数来更改s 位置

    struct ball
    {
        int heading = north_east;
        bool visible = true;
        int pos_x = ball_start_x;
        int pos_y = ball_start_y; 
        char c = 'o';
    };

    void move_ball(ball *target_ball)
    {
        switch (target_ball->heading)
        {
            case north_east: 
            {
                target_ball->pos_x ++ ;
                target_ball->pos_y -- ;
            }
            case north_west:
            {
                target_ball->pos_x -- ;
                target_ball->pos_y -- ;
            }
            case south_west:
            {
                target_ball->pos_x ++ ;
                target_ball->pos_y ++ ;
            }
            case south_east:
            {
                target_ball->pos_x -- ;
                target_ball->pos_y ++ ;
            }
        }
    }
    
    
    int main(){
        ball ball_no_1;
        move_ball(&ball_no_1);
    }

但即使我通过引用调用它们，位置似乎也没有改变！

请帮我...

Answer 1

你忘了一堆break语句，case north_east后面的所有行都执行了，加二减二的结果是0

switch (target_ball->heading)
        {
            case north_east: 
            {
                target_ball->pos_x ++ ;
                target_ball->pos_y -- ;
                break;
            }
            case north_west:
            {
                target_ball->pos_x -- ;
                target_ball->pos_y -- ;
                break;
            }
            case south_west:
            {
                target_ball->pos_x ++ ;
                target_ball->pos_y ++ ;
                break;
            }
            case south_east:
            {
                target_ball->pos_x -- ;
                target_ball->pos_y ++ ;
                break;
            }
        }