Compilare: main.cpp: In function 'std::__cxx11::string perm(long long int)': main.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <=c; i++) { ~~^~~ main.cpp:19:23: 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:48:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) { ~~^~~ main.cpp:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ~~^~~ main.cpp:64:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < n; i++) ~~^~~ main.cpp:69:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ~~^~~ main.cpp:77:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ~~^~~ main.cpp:44:13: warning: iteration 59 invokes undefined behavior [-Waggressive-loop-optimizations] fact[i] = fact[i - 1] * i; ~~~~~~~~^~~~~~~~~~~~~~~~~ main.cpp:43:21: note: within this loop for (int i = 1; i <= 60; i++) ~~^~~~~