C语言使用枚举输出一周中的每一天
下面的程序将输出一周中的每一天：
today yesterday tomorrow
============================================
monday = 0 sunday = 6 tuesday = 1
tuesday = 1 monday = 0 wednesday = 2
wednesday = 2 tuesday = 1 thursday = 3
thursday = 3 wednesday = 2 friday = 4
friday = 4 thursday = 3 saturday = 5
saturday = 5 friday = 4 sunday = 6
sunday = 6 saturday = 5 monday = 0
#include <stdio.h>
// 定义枚举类型
enum days {monday,tuesday,wednesday,thursday,friday,saturday,sunday};
typedef enum days days; // 我们可以使用 days 来代替 enum days
days yesterday(days today){
return (today+6)%7;
}
days tomorrow(days today){
return (today+1)%7;
}
// 常量字符串数组
const char * const thedays[] = {"monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday"};
int main(void){
days today;
printf("today \tyesterday \ttomorrow\n"
"============================================\n");
for (today=monday;today<=sunday;today++)
printf("%s = %d \t %s = %d \t %s = %d\n",
thedays[today], today,
thedays[yesterday(today)], yesterday(today),
thedays[tomorrow(today)], tomorrow(today));
}
输出结果：today yesterday tomorrow
============================================
monday = 0 sunday = 6 tuesday = 1
tuesday = 1 monday = 0 wednesday = 2
wednesday = 2 tuesday = 1 thursday = 3
thursday = 3 wednesday = 2 friday = 4
friday = 4 thursday = 3 saturday = 5
saturday = 5 friday = 4 sunday = 6
sunday = 6 saturday = 5 monday = 0
