Compilare: main.cpp: In function 'int main()': main.cpp:44:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 44 | for (i=0; i<s1.size(); i++) | ~^~~~~~~~~~ main.cpp:47:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 47 | for (i=0; i<s.size(); i++) | ~^~~~~~~~~ main.cpp:50:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for (i=0; i<s.size(); i++){ | ~^~~~~~~~~