Compilare: user.cpp: In function ‘int main()’: user.cpp:47: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:50: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘long long int urm_prim(long long int&)’: user.cpp:21: warning: control reaches end of non-void function