Compilare: main.cpp: In function 'int main()': main.cpp:102:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 102 | for (i=0; i<s.size(); i++) | ~^~~~~~~~~ main.cpp:112:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 112 | for (i=0; i<s.size(); i++) | ~^~~~~~~~~ main.cpp:120:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 120 | for (i=0; i<s.size(); i++) | ~^~~~~~~~~