Compilare: user.cpp: In function ‘int pct(int, int)’: user.cpp:16:9: warning: unused variable ‘ca’ [-Wunused-variable] int ca=a; ^ user.cpp: In function ‘int main()’: user.cpp:27:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:29:41: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&v[i].x,&v[i].y); ^