找不到符号 - 方法guess（）

Question

我是java的新手，我正在努力理解基础知识。因此，我无法理解为什么这不会编译。

错误出现在int guess = input.guess();上，它表示无法找到符号 - 方法guess（）。

提前感谢您提供任何帮助

public class HiLo
{
    private int upper;
    private int randomNumber;
    private Input input;
    private boolean won;
    private int guesses;

    public HiLo(int x)
    {
        upper = x-1;
        randomNumber = (int)(Math.random() * upper)+1;
        input = new Input();
        won = false;
        guesses = 10;
    }

    public void playHumanGame()
    {
        while ((won == false) && (guesses > 0))
        {
            int guess = input.guess();
            guesses--;
            if (guess > randomNumber)
            {
                System.out.println("You're too high pal");
            }
            else if (guess < randomNumber)
            {
                System.out.println("You're not high enough");
            } 
            else 
            {
                System.out.println("You won the game... Well done I suppose...");
                won = true;
            }
        }
    }
}