1.warning C4996: 'setmode': The POSIX name for this item is deprecated. Instead, use the ISO C++ conformant name: _setmode. See online help for details.
增加宏定义去掉这种类似的警告：_CRT_NONSTDC_NO_DEPRECATE
2. 去掉线程安全警告，定义宏：_CRT_SECURE_NO_WARNINGS