Compilare: main.cpp: In function 'int main()': main.cpp:40:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 40 | for(int i = 0; i < str.size(); ++i) | ~~^~~~~~~~~~~~ main.cpp:49:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | while(i < str.size() && str[i] >= '0' && str[i] <= '9') | ~~^~~~~~~~~~~~