combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:38:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
38 | if (y==ans.size())ans+=x[2];
| ~^~~~~~~~~~~~
combo.cpp:39:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
39 | if (y==ans.size()+1)ans+=x[0];
| ~^~~~~~~~~~~~~~
combo.cpp:40:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
40 | if (y==ans.size()+2)ans+=x[1];
| ~^~~~~~~~~~~~~~
combo.cpp:6:12: warning: control reaches end of non-void function [-Wreturn-type]
6 | string ans, x;
| ^~~