Compilare: main.cpp: In function 'symbol parse_next()': main.cpp:28:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | if(idx >= s.size()) { | ~~~~^~~~~~~~~~~ main.cpp:45:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 45 | while(idx < s.size() && isdigit(s[idx])) { | ~~~~^~~~~~~~~~