Compilare: main.cpp: In function 'char* cerinta2()': main.cpp:15:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 15 | for( int i = 2; i < a.size(); ++i ) { | ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:39:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 39 | for( int i = 1; i <= a.size(); ++i ) { | ~~^~~~~~~~~~~