Compilare: main.cpp: In function 'std::__cxx11::string perm(long long int)': main.cpp:18:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <=c; i++) { ~~^~~ main.cpp:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < n; j++) { ~~^~~ main.cpp: In function 'int main()': main.cpp:49:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) { ~~^~~ main.cpp:60:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ~~^~~ main.cpp:65:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < n; i++) ~~^~~ main.cpp:70:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ~~^~~ main.cpp:78:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ~~^~~ main.cpp:46:13: warning: iteration 59 invokes undefined behavior [-Waggressive-loop-optimizations] fact[i] = fact[i - 1] * i; ~~~~~~~~^~~~~~~~~~~~~~~~~ main.cpp:45:21: note: within this loop for (int i = 1; i <= 60; i++) ~~^~~~~