来个分析答案，C语言程序

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

struct Student//声明结构体类型：struct student

{

char name[20];//以下四行为结构体的成员

double math;

double english;

double chinese;

};

voidinput_score(struct Student[]);//声明input_score函数

voidreorder(struct Student[]);//声明reoder函数

voidswitch_number(struct Student*, struct Student*);//声明swhich_number函数

intstudent_cmp(struct Student*, struct Student*);//声明student_cmp函数

voidstudnet_display(struct Student[]);//声明student_display函数

int main(){

struct Student stus[3];

input_score(stus);

studnet_display(stus);

reorder(stus);

studnet_display(stus);

}

voidinput_score(struct Student stu[]) {//定义input_score函数

int i;

for (i = 0;i <3;i++) {

    printf("请输入第%d位同学的姓名:", i + 1);

    scanf_s("%s", stu[i].name, 20);

    printf("请输入第%d位同学的英语成绩:", i + 1);

    scanf_s("%lf", &stu[i].english);

    printf("请输入第%d位同学的数学成绩:", i + 1);

    scanf_s("%lf", &stu[i].math);

    printf("请输入第%d位同学的语文成绩:", i + 1);

    scanf_s("%lf", &stu[i].chinese);

    printf("\n");

}

}

intstudent_cmp(struct Student* stu1, struct Student*stu2) {//定义student_cmp函数

double sum1, sum2;

sum1= stu1->chinese + stu1->english + stu1->math;

sum2= stu2->chinese + stu2->english + stu2->math;

if (sum1 != sum2) {

    return sum1 - sum2;

}

else if (stu1->math != stu2->math) {

    return stu1->math - stu2->math;

}

else {

    return stu1->chinese - stu2->chinese;

}

}

voidswitch_number(struct Student* stu1, struct Student* stu2) {//定义swhich_number函数

double ls;//定义中间变量

char sls[20];

ls= stu1->chinese;

stu1->chinese = stu2->chinese;

stu2->chinese = ls;

ls= stu1->math;

stu1->math = stu2->math;

stu2->math = ls;

ls= stu1->english;

stu1->english = stu2->english;

stu2->english = ls;

strcpy_s(sls,20, stu1->name);

strcpy_s(stu1->name, 20, stu2->name);

strcpy_s(stu2->name, 20, sls);

}

voidreorder(struct Student stu[]) {//定义reorder函数

int i, j;

for (i = 0;i <3;i++) {

    for (j = i;j <3;j++) {

        if (student_cmp(&stu[i], &stu[j]) < 0) {

            switch_number(&stu[j], &stu[i]);

        }

    }

}

}

voidstudnet_display(struct Student stu[]) {//定义student_display函数

int i;

printf("%-20s%-20s%-20s%-20s\n", "姓名", "语文成绩", "英语成绩", "数学成绩");

for (i = 0;i <3;i++) {

    printf("%-20s %-20.2f %-20.2f %-20.2f\n", stu[i].name, stu[i].chinese, stu[i].english, stu[i].math);//按要求输出学生的各科成绩

}

}