#include<stdio.h>
#include<stdlib.h>
#define N 3
struct Student{
    int num;
    char name[20];
    float score[3];
    float aver;
};
int main()
{
    void input(struct Student stu[]);
    struct Student max(struct Student stu[]);
    void print(struct Student stu[]);
    struct Student stu[N],*q, *p=stu;
    print(max(p));  /这里显示不存在从student到student*的函数转换？
    system("pause");
    return 0;
}
void input(struct Student stu[])
{
    int i;
    printf("请输入各学生的信息：学好、姓名、三门课成绩：");
    for (i = 0; i < N; i++)
    {
        scanf("%d %s %f %f %f", &stu[i].num, stu[i].name, &stu[i].score[0], &stu[i].score[1], &stu[i].score[2]);
        stu[i].aver = (stu[i].score[0] + stu[i].score[1] + stu[i].score[2]) / 3;
    }
}
    struct Student max(struct Student stu[])
    {
        int i, m = 0;
        for (i = 0; i < N;i++)
         if (stu[i].aver > stu[m].aver)
            m = i;
         return stu[m];
    }
    void print(struct Student stu)
    {
        printf("\n成绩最高的学生是：\n");
        printf("学好：%d\n姓名：%s\n%三门课成绩：%5.1f,%5.1f,%5.1f\n平均成绩：%6.2f\n", stu.num, stu.name, stu.score[0],
            stu.score[1], stu.score[2], stu.aver);
    }

print函数声明的参数和实际的参数不一样，一个是数组，一个是student。

void print(struct Student stu[]);
void print(struct Student stu){...}
不一样，什么鬼？