Compilare: user.cpp: In function ‘int main()’: user.cpp:17:15: warning: unused variable ‘lg’ [-Wunused-variable] int N, x, lg = 0, op = 0, rad; ^ user.cpp:17:31: warning: unused variable ‘rad’ [-Wunused-variable] int N, x, lg = 0, op = 0, rad; ^ user.cpp:19:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf ( f, "%d", &N ); ^