Compilare: user.cpp: In function ‘void ReadInput()’: user.cpp:39:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ends.resize(n); ^ user.cpp:42:62: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int x1, y1, x2, y2; scanf("%d%d%d%d", &x1, &y1, &x2, &y2); ^ user.cpp: In function ‘void BuildSystem()’: user.cpp:84:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int state; scanf("%d", &state); ^