在C变量声明安置 [英] Variable declaration placement in C

问题描述

我一直认为，在C，所有变量都必须在函数的开始申报。我知道，在C99中，规则是一样的在C ++中，但什么是变量声明放置规则为C89 / ANSI C？

I long thought that in C, all variables had to be declared at the beginning of the function. I know that in C99, the rules are the same as in C++, but what are the variable declaration placement rules for C89/ANSI C?

以下code与成功编译的gcc -std = C89 和的gcc -ansi ：

#include <stdio.h>
int main() {
    int i;
    for (i = 0; i < 10; i++) {
        char c = (i % 95) + 32;
        printf("%i: %c\n", i, c);
        char *s;
        s = "some string";
        puts(s);
    }
    return 0;
}

不应该的C中的声明和取值引起C89 / ANSI模式错误？

Shouldn't the declarations of c and s cause an error in C89/ANSI mode?

推荐答案

它编译成功，因为GCC允许它作为一个GNU扩展，即使它不是C89或ANSI标准的一部分。如果要严格遵守这些标准，你必须通过 -pedantic 标记。

It compiles successfully because GCC allows it as a GNU extension, even though it's not part of the C89 or ANSI standard. If you want to adhere strictly to those standards, you must pass the -pedantic flag.

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