能举个用结构体写的程序例子

#include<stdio.h>

#define STNUM 3 //学生数 

struct student{

char id[10]

char name[10]

float course[3]

}

int main(){

student st[STNUM] //student结构体数组 

int i,j

printf("==========录入信息==========\n")

for(i=0i<STNUMi++){

printf("请输入第%d个学生的信息\n",i+1)

printf("请输入学号：")

scanf("%10s",&st[i].id)

printf("请输入姓名：")

scanf("%10s",&st[i].name)

printf("请输入3门课的成绩：")

for(j=0j<3j++){

scanf("%f",&st[i].course[j])

sum[i] += st[i].course[j]

}

}

printf("==========学生信息==========\n")

for(i=0i<STNUMi++){

printf("-----------学生%d----------\n",i+1)

printf("学号：%s\n",st[i].id)

printf("姓名：%s\n",st[i].name)

printf("3门课的成绩：")

for(j=0j<3j++){

printf("%.1f ",st[i].course[j])

sum[i] += st[i].course[j]

}

printf("\n")

}

return 0

}

enum WeekDay {Monday=0, Tuesday, Wednesday, Thursday, Friday, Staturday, Sunday}

char *name[] = { "Monday",

"Tuesday",

"Wednesday",

"Thursday",

"Friday",

"Saturday",

"Sunday"

}

typedef struct date

{

int year

int month

int day

enum WeekDay weekday

}date

int main()

{

date d

printf("Day: ")fflush(stdout)

scanf("%d",&d.day)

printf("Month: ")fflush(stdout)

scanf("%d",&d.month)

printf("Year: ")fflush(stdout)

scanf("%d",&d.year)

if ((d.month == 1) || (d.month == 2)){

d.month += 12

d.year--

}

d.weekday = (WeekDay)((d.day + 2*d.month + 3*(d.month+1)/5 + d.year + d.year/4 - d.year/100 + d.year/400) % 7)

printf("%d-%d-%d is %s.\n",d.year, d.month, d.day, name[d.weekday])

return 0

}

其中的公式参考：

http://www.cppblog.com/qywyh/articles/14021.html

希望能解决你的问题

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