Compilare: user.cpp: In function ‘int main()’: user.cpp:17:36: warning: operation on ‘j’ may be undefined [-Wsequence-point] for(j=i+i; j<=n; j=j=j+i) ^ user.cpp:32:29: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 3 has type ‘long long int’ [-Wformat=] fprintf(g,"%ld\n",nr); ^ user.cpp:11:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%lld" , &n); ^ user.cpp:21:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%lld" , &x); ^ user.cpp:24:39: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%lld%lld" , &x1,&y); ^