Compilare: main.cpp: In function 'int main()': main.cpp:20:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | for (int i=0; i<s.length(); i++) | ~^~~~~~~~~~~ main.cpp: In function 'long long int combinatorica(long long int, long long int)': main.cpp:39:24: warning: unused variable 'kfact' [-Wunused-variable] 39 | long long nfact=1, kfact=1, nkfact=1, ans=1; | ^~~~~