'bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)'

error C2784: 'bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)' : could not deduce template argument for 'const std::_Tree<_Traits> &' from 'const std::string' 

 

解决：头文件添加#include <string>