Compilare: main.cpp: In function 'int main()': main.cpp:2:64: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] using namespace std;int main(){freopen("fetite.in", "r", stdin);freopen("fetite.out", "w", stdout);unsigned long long N, R, I = 2;for(cin >> N; I <= N; I *= 2) R = I;cout << (N - R)*2 + 1;} ^ main.cpp:2:99: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] using namespace std;int main(){freopen("fetite.in", "r", stdin);freopen("fetite.out", "w", stdout);unsigned long long N, R, I = 2;for(cin >> N; I <= N; I *= 2) R = I;cout << (N - R)*2 + 1;} ^ main.cpp:2:178: warning: 'R' may be used uninitialized in this function [-Wmaybe-uninitialized] using namespace std;int main(){freopen("fetite.in", "r", stdin);freopen("fetite.out", "w", stdout);unsigned long long N, R, I = 2;for(cin >> N; I <= N; I *= 2) R = I;cout << (N - R)*2 + 1;} ~~~^~~~