Compilare: user.cpp: In function ‘int main()’: user.cpp:17:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=1; k <= cases; k++){ ^ user.cpp:13:27: warning: unused variable ‘i’ [-Wunused-variable] unsigned long long int k,i; ^ user.cpp:5:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("quadratum.in","r",stdin); ^ user.cpp:6:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("quadratum.out","w",stdout); ^ user.cpp:10:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&cases); ^ user.cpp:19:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&n); ^