Compilare: user.cpp: In function ‘void check_square(long long unsigned int)’: user.cpp:73:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (rad = 1; 1LL * rad * rad <= A; rad++); ^ user.cpp:75:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (1LL * rad * rad != A) ^ user.cpp: In function ‘int main()’: user.cpp:86:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ubercool.in","r",stdin); ^ user.cpp:87:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ubercool.out","w",stdout); ^ user.cpp:89:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:96:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%llu", &X); ^