Compilare: user.cpp: In function ‘int main()’: user.cpp:9:21: warning: unused variable ‘r’ [-Wunused-variable] float x=sqrt(5),r; ^ user.cpp:6:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pietre.in","r",stdin); ^ user.cpp:7:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pietre.out","w",stdout); ^ user.cpp:10:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld ",&t); ^ user.cpp:15:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld ",&a,&b); ^