# include<stdio.h>
# include<malloc.h>

struct student
{
    int age;
    float score;
    char name[100];
};

void inputstudent(struct student * a, int len)
{
    int i;
    for(i=0; i<len; ++i)
    {
        printf("请输入第%d个人的信息：\n", i+1);
        printf("name是：");
        scanf("%s", a[i].name);
        printf("age = ");
        scanf("%d", &a[i].age);
        printf("score = ");
        scanf("%f", &a[i].score);

    }
}

order(struct student * c, int len)
{
    int i, j;
    struct student t;
    for(i=0; i<len-1; ++i)
        for(j=0; j<len-1-i; ++j)
        {
            if(c[j].score < c[j+1].score)
            {
                t = c[j];
                c[j] = c[j+1];
                c[j] = t;

            }
        }

}

void outputstudent(struct student * b, int len)
{
    int i;
    for(i=0; i<len; ++i)
    {
        printf("name是：%s\n", b[i].name);
        printf("age = %d\n", b[i].age);
        printf("score = %f\n", b[i].score);
    }

}

int main(void)
{
    int len;

    printf("请输入学生的个数：\n");
    printf("len = ");
    scanf("%d", &len);

    struct student * st;
    st = (struct student *)malloc(sizeof(struct student));


    inputstudent(st, len);

    order(st, len);

    outputstudent(st, len);

    return 0;
}
为什么不能正常排序呢？

t = c[j];
 c[j] = c[j+1];
c[j+1] = t;