【GCC警告&报错7】error: a label can only be part of a statement and a declaration is not a statement

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文章发布于：《C语言编译报错&警告合集》

例子：

编译报错：

原因：
Prior to C99, all declarations had to precede all statements within a block, so it wouldn’t have made sense to have a label on a declaration. C99 relaxed that restriction, permitting declarations and statement to be mixed within a block, but the syntax of a labeled-statement was not changed.
即使在C99中，声明前不能加上标签，这是无意义的。例子中int