Compilare: user.cpp: In function ‘long long unsigned int gen_fact()’: user.cpp:11:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘long long unsigned int pow(long long unsigned int, long long unsigned int)’: user.cpp:15:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int p = 1; p <= exp; p <<= 1) { ^ user.cpp: In function ‘int main()’: user.cpp:37:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (k == n.size() - 1) { ^