Compilare: main.cpp: In function 'int main()': main.cpp:37:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for ( int i = 0 ; i < a.size() ; i ++ ) | ~~^~~~~~~~~~