Compilare: main.cpp: In function 'int main()': main.cpp:61:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | for (int i = 0; i < s1.size(); i++) | ~~^~~~~~~~~~~ main.cpp:71:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 71 | for (int i = 0; i < s2.size(); i++) | ~~^~~~~~~~~~~ main.cpp:81:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 81 | for (int i = 0; i < s3.size(); i++) | ~~^~~~~~~~~~~