Compilare: user.cpp: In function ‘int main()’: user.cpp:44:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<low.size();i++){ ^ user.cpp:48:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<up.size();i++) ^ user.cpp:24:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&n); ^ user.cpp:26:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&v[i].x,&v[i].y); ^