程序代码：

root@~ #cat 1.c
#include <stdio.h>
struct student {
        int id;
        int sa;
        int sb;
        int sc;
};

int main (void) {
        struct student a,b,c,d,e; //定义5个学生的结构
        struct student input (struct student boy);
        void display (struct student boy);
//录入数据
        a=input(a);
        b=input(b);
        c=input(c);
        d=input(d);
        e=input(e);

//显示5个学生的各科成绩总分等。
        display(a);
        display(b);
        display(c);
        display(d);
        display(e);

        return 0;

}

struct student input (struct student boy) {

                printf ("Enter id:");
                scanf ("%i",&boy.id);
                printf ("Enter score a:");
                scanf ("%i",&boy.sa);
                printf ("Enter score b:");
                scanf ("%i",&boy.sb);
                printf ("Enter score c:");
                scanf ("%i",&boy.sc);

                return boy;

}
void display (struct student boy) {

        printf (" \nboy id:%i\n",boy.id);
        printf ("score a:%i\n",boy.sa);
        printf ("score b:%i\n",boy.sb);
        printf ("score c:%i\n",boy.sc);
        printf ("Sum of score:%i\n",boy.sa+boy.sb+boy.sc);
        printf ("Average of score:%.2f\n",(float)(boy.sa+boy.sb+boy.sc)/3);

}