Compilare: main.cpp: In function 'int main()': main.cpp:25:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | for(int i=0; i<a.size(); i++) { | ~^~~~~~~~~ main.cpp:28:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | for(int i=0; i<b.size(); i++) { | ~^~~~~~~~~ main.cpp:35:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 35 | for(int i=0; i<a.size(); i++) { | ~^~~~~~~~~