#include<stdio.h>
struct student
{
    int number;
    char name[7];
    float score;
};
int main()
{
    struct student stu[5] = { {01,"GY",97},{02,"Yoo",87},{03,"Gong",87.7},{04,"shacha",97.7},{05,"erzi",77} };
    struct student t;
    int i, j, k;
    for (i = 3; i >=0; i--)                                                  //
    {
        k = i;                                                            这
        for (j = i + 1; j >0; j--)
        {
            if (stu[k].score < stu[j].score)                          部
                k = j;
            t = stu[i]; stu[i] = stu[k]; stu[k] = t;                  分
        }                                                      
    }                                                                         //
    for (i = 0; i < 5; i++)
        printf("%6d %8s %6.2f\n", stu[i].number, stu[i].name, stu[i].score);
    return 0;
}
而下面这样就不同了

for (i = 0; i <4; i++)
    {
        k = i;
        for (j = i + 1; j <5; j++)
        {
            if (stu[k].score < stu[j].score)
                k = j;
            t = stu[i]; stu[i] = stu[k]; stu[k] = t;
        }
    }




或者以下两种,为什么结果不同？？？
for (i = 0; i <4; i++)
    {
        k = i;
        for (j = i + 1; j <5; j++)
        {
            if (stu[j].score >stu[k].score)
                k = j;
            t = stu[i]; stu[i] = stu[k]; stu[k] = t;
        }
    }

for (i = 0; i <4; i++)
    {
        k = i;
        for (j = i + 1; j <5; j++)
        {
            if (stu[k].score < stu[j].score)
                k = j;
            t = stu[i]; stu[i] = stu[k]; stu[k] = t;
        }
    }

为什么要k=i??

不赋值的话为什么不行

不是。
为什么
    for (i = 3; i >=0; i--)
    {
        for (j = i + 1; j >0; j--)
            if (stu[i].score < stu[j].score)
            {
                t = stu[i]; stu[i] = stu[j]; stu[j] = t;
            }
    }
这样不行？

不对，发错了
for (i = 4; i >=0; i--)
    {
        for (j = i -1; j >0; j--)
            if (stu[i].score >stu[j].score)
            {
                t = stu[i]; stu[i] = stu[j]; stu[j] = t;
            }
    }
我就拿你写的例子写了一遍下来是没问题，但是电脑不行
         j i
   5 1 3 4 2
（1）5 1 3 4 2
（2）5 2 3 4 1
（3）5 2 4 3 1
（4）5 3 4 2 1
（5）5 4 3 2 1

！！！感觉自己蠢，拜谢拜谢

俺不想再赋值呐，拜谢拜谢！