Compilare: main.cpp: In function 'int parseNumber(std::string&, int&)': main.cpp:13:19: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 13 | while(str.size() > pos && '0' <= str[pos] && str[pos] <= '9') | ~~~~~~~~~~~^~~~~ main.cpp: In function 'void parseEquation(std::string&, int&, int&)': main.cpp:24:19: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 24 | while(str.size() > pos) | ~~~~~~~~~~~^~~~~ main.cpp:36:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | if(pos < str.size() && str[pos] == VARIABLE) | ~~~~^~~~~~~~~~~~