Compilare: main.cpp: In function 'int main()': main.cpp:21:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 21 | for( j = 0; j < s[i].size(); j++ ) { | ~~^~~~~~~~~~~~~ main.cpp:31:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | for( i = 0; i < s[0].size(); i++ ) { | ~~^~~~~~~~~~~~~