CC99C++C++xGNU CGNU C99 中枚举的符号

枚举（Enum）在编程语言中是一种数据类型，它定义了一个可选值集合。在C/C99/C++/C++x/GNU C/GNU C99中，枚举符号是用来表示这些可选值的标识符。枚举类型可以用来定义一组相关的常量，使程序更加易读和易维护。

c
enum Weekday {
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
};

c
#include 
enum Weekday {
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
};
int main() {
    enum Weekday today = Monday;
    
    printf("Today is ");
    
    switch (today) {
        case Monday:
            printf("Monday");
            break;
        case Tuesday:
            printf("Tuesday");
            break;
        case Wednesday:
            printf("Wednesday");
            break;
        case Thursday:
            printf("Thursday");
            break;
        case Friday:
            printf("Friday");
            break;
        case Saturday:
            printf("Saturday");
            break;
        case Sunday:
            printf("Sunday");
            break;
        default:
            printf("Unknown");
            break;
    }
    
    return 0;
}