Compilare: user.cpp: In function ‘int main()’: user.cpp:63:18: warning: left operand of comma operator has no effect [-Wunused-value] for(i=1;i<=pr[0],pr[i] <= sqrt((double)n);i++) { ^ user.cpp:47:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sumdiv2.in","r",stdin); ^ user.cpp:48:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sumdiv2.out","w",stdout); ^ user.cpp:50:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld\n",&q); ^ user.cpp:53:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld\n",&qu[i].a,&qu[i].b); ^