error C2275: 'xxx' : illegal use of this type as an expression

很多时候程序出现莫名其妙的错误提示：

error C2275: 'xxx' : illegal use of this type as an expression

这很多时候是标准的C编译器是要求定义必须在程序开头定义造成的，C98标准了，C99也要求，在C++中，这个要求不是很严格，也就是说在程序中也可以定义变量。

(declaration)must placed on the beginning of function,
In this case, the compile option is

key. In VC default compile option, there no problem. But when compile option is strict, this style

of writting can not compile with success.

这时把变量定提前到函数开头就可以解决