enum cases { enterArray = 1, randomArray = 2, fromFile = 3, exit = 4 };
	while (true)
	{
		cout << "Press 1 to enter array.\n";
		cout << "Press 2 to make random array.\n";
		cout << "Press 3 to get array from file.\n";
		cout << "Press 3 to exit.\n";
		int n;
		cin >> n;
		system("cls");

		switch (n)
		{
		case enterArray:

			break;
		case randomArray:

			break;
		case fromFile:

			break;
		case exit:
			return;
		default:
			cout << "Invalid operation. Try again.\n";
			system("pause");
			system("cls");
		}
	}