Compilare: user.cpp: In function ‘int main()’: user.cpp:49:11: warning: suggest parentheses around assignment used as truth value [-Wparentheses] if(x1=0) ^ user.cpp:11:10: warning: variable ‘n1’ set but not used [-Wunused-but-set-variable] int n0, n1, n2, k, x1, x2, y1, y2, i; ^ user.cpp:13:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d", &n0, &k); ^ user.cpp:27:46: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d %d %d", &x1, &y1, &x2, &y2); ^