Compilare: main.cpp: In function 'int main()': main.cpp:58:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 58 | if (z[i] == a.size()) | ~~~~~^~~~~~~~~~~ main.cpp:70:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 70 | if (z[i] == a.size()) | ~~~~~^~~~~~~~~~~ main.cpp:80:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 80 | if (z[i] == a.size()) | ~~~~~^~~~~~~~~~~