Compilare: user.cpp: In function ‘int main()’: user.cpp:16:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,n; ^ user.cpp:17:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:19:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%lf %lf",&v[i].x,&v[i].y); ^