Compilare: main.cpp: In function 'int main()': main.cpp:35:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 35 | if (len == a.size()) | ~~~~^~~~~~~~~~~ main.cpp:43:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 43 | for (int j = 0; j < a.size(); j++) | ~~^~~~~~~~~~ main.cpp:53:44: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 53 | for (i = a.size() - len; i < a.size() - 1; i++) | ~~^~~~~~~~~~~~~~ main.cpp:61:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | for (i += 2; i < a.size(); i++) | ~~^~~~~~~~~~ main.cpp:80:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 80 | for (i++; i < a.size(); i++) | ~~^~~~~~~~~~