Compilare: user.cpp: In function ‘int main()’: user.cpp:44:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(IN,"%d%d",&M,&N); ^ user.cpp:50:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(IN,"%d",&X); ^ user.cpp: In function ‘void Get_Primes()’: user.cpp:18:16: warning: iteration 1999u invokes undefined behavior [-Waggressive-loop-optimizations] fr[i]=1; ^ user.cpp:17:5: note: containing loop for(int i=2;i<MaxN;i+=2) ^