如何让我的程序打印出来？

Question

无法让我的程序适用于我的AP计算机科学课程。已在代码中发表评论以显示我的问题。谢谢你们/ gals。

Java类

import java.util.*;
public class Allosaur extends Dinosaur
{
private boolean hungry;
private String response, answer;
private String Allosaur;

 // Prompt asks for 3 constructors: A Default constructor, a constructor with just a name, and a constructor with a name and hunger "response"

public Allosaur()
{
}

public Allosaur(String name)
{
 Allosaur=name;   
}

public Allosaur(String name, boolean hungry)
{
    Allosaur=name;
    this.hungry=hungry;
}

// Used this method to "find out" whether the dinosaur is hungry or not
public boolean getHunger()

{
    Scanner keyboard = new Scanner(System.in);
    System.out.println("Are you hungry? ");
    response = keyboard.next();
    if(response.equals("Yes"))
    hungry = true;
    else if(!response.equals("Yes"))
    hungry= false;

    return hungry;

}

// Asks us to print out "RRRRRRR" if the dinosaur is NOT hungry and "HUNGRRRRRRRY" if the dinosaur IS hungry   

public String roar()
{
    if(hungry == true)
    answer = "HUNGRRRRRRRY";
    else if(hungry == false)
    answer = "RRRRRRR";

    return answer;
}

//When I use the toString() method in my driver class, none of these pop up, why?

public String toString()
{
    String Dino = super.toString();
    Dino = "The Dinosaur's name is: " + Allosaur;
    Dino += "Is the Dinosaur hungry? :" + getHunger() + "\n" + roar();
    return Dino;

} 

}

这是我的驱动程序类：

public class DinosaurMain extends Allosaur
{
public static void main(String[] args) 
{
       Allosaur Dino = new Allosaur("Jacob");
       Dino.toString();

}

}

我很困惑为什么在我运行程序时什么都不会出现。

Answer 1

请求String输入后没有显示任何内容，因为您只是在DinosaurMain中以Dino.toString()进行调用。这只是为您的对象创建String表示。它没有打印出String表示。如果您要将其更改为System.out.println(Dino.toString());，您会看到结果。