Compilare: user.cpp: In function ‘long long int multiply(long long int, long long int)’: user.cpp:12:31: warning: operation on ‘a’ may be undefined [-Wsequence-point] a = (a <<= 1) % modulo; ^ user.cpp: In function ‘int main()’: user.cpp:20:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("valuare.in", "r", stdin); ^ user.cpp:21:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("valuare.out", "w", stdout); ^ user.cpp:23:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld", &base, &modulo); ^