warning: its scope is only this definition or declaration, which is not what you want
warning:itsscopeisonlythisdefinitionordeclaration,whichisnotwhatyouwantC语言编译出错,出错处理是:将声明对应的文件放在前部,以保证该声明在使用前已经被找到。参考http://cboard.cprogramming.com/c-programming/166621-warning-its-scope-only-definitio