error: ‘to_string’ was not declared in this scope
错误：error: ‘to_string’ was not declared in this scope原因：to_string是C++11引入的新功能，旧版本编译器可能不支持它，所以要给编译器加上“C++11”编译支持解决方案：Linux下的GCC编译器：在 g++ 命令行加入编译选项-std=c++11，例如：g++ -o test test.cpp ...
