#include<stdio.h>
#include<conio.h>
char tou;
enum FX
{
    up = 72, down = 80, left = 75, right = 77
};
void changfx_()
{
    char key;
    if ((key = _getch()) < 0)
    {
        key = _getch();
    }
    switch (key)
    {
    case up:
        if (key != down)
            tou = up;
        break;
    case down:
        if (key != up)
            tou = down;
        break;
    case right:
        if (key != left)
            tou = right;
        break;
    case left:
        if (key != right)
            tou = left;
        break;
    }

}
int main()
{
    while (1)
    {
        changfx_();
        printf("方向为=%d\n", tou);
    }
}

输入一个上之后，tou=up（上），然后输入down（下）条件语句不能为down，头依然为up

。。。  原来条件设置的问题在这里  感谢感谢