在switch语句中使用enum类型

I am using a switch statement to return from my main function early if some special case is detected. The special cases are encoded using an enum type, as shown below.

如果检测到某些特殊情况，我正在使用switch语句提前从我的main函数返回。特殊情况使用枚举类型进行编码，如下所示。

typedef enum {
    NEG_INF,
    ZERO,
    POS_INF,
    NOT_SPECIAL
} extrema;

int main(){

    // ...

    extrema check = POS_INF;

    switch(check){
        NEG_INF: printf("neg inf"); return 1;
        ZERO: printf("zero"); return 2;
        POS_INF: printf("pos inf"); return 3;
        default: printf("not special"); break;
    }

    // ...

    return 0;

}

Strangely enough, when I run this, the string not special is printed to the console and the rest of the main function carries on with execution.

奇怪的是，当我运行它时，字符串不是特殊的打印到控制台，主要功能的其余部分继续执行。

How can I get the switch statement to function properly here? Thanks!

如何让switch语句在这里正常运行？谢谢！

3 个解决方案

#1

No case labels. You've got goto labels now. Try:

没有案例标签。你现在有了goto标签。尝试：

switch(check){
    case NEG_INF: printf("neg inf"); return 1;
    case ZERO: printf("zero"); return 2;
    case POS_INF: printf("pos inf"); return 3;
    default: printf("not special"); break;
}

#2

You're missing the all-important case:

你错过了最重要的案例：

switch(check){
    case NEG_INF: printf("neg inf");     return 1;
    case ZERO:    printf("zero");        return 2;
    case POS_INF: printf("pos inf");     return 3;
    default:      printf("not special"); break;
}

You created some (unused) labels with the same names as your enumeration constants (which is why it compiled).

您创建了一些（未使用的）标签，其名称与枚举常量相同（这就是它编译的原因）。

#3

You haven't used the keyword "case". The version given below will work fine.

您还没有使用关键字“case”。下面给出的版本可以正常工作。

typedef enum {
    NEG_INF,
    ZERO,
    POS_INF,
    NOT_SPECIAL

} extrema;

int main(){

    extrema check = POS_INF;

    switch(check){
        case NEG_INF: printf("neg inf"); return 1;
        case ZERO: printf("zero"); return 2;
        case POS_INF: printf("pos inf"); return 3;
        default: printf("not special"); break;
    }

    return 0;

}

#1