Question

我正在寻求一些帮助。我坐在家里试图从programmingbydoing.com学习java编程。我需要制作一个名为TwentyQuestions的程序。代码缺少一些东西，使它完全工作。我试图在网上找到其他地方的帮助。这就是为什么代码看起来很像其他人的代码。

import java.util.Scanner;

public class TwentyQuestions
{
    public static void main( String[] args )
    {
        Scanner keyboard = new Scanner(System.in);

        String type, size, guess = "";

        System.out.println("TWO QUESTIONS!");
        System.out.println("Think of an object, and I'll try to guess it.");
        System.out.println("");

        System.out.println("Question 1) Is it animal, vegetable or mineral?");
        System.out.print("> ");
        type = keyboard.next();
        System.out.println("");

        System.out.println("Question 2) Is it bigger than a breadbox?");
        System.out.print("> ");
        size = keyboard.next();
        System.out.println("");

        if (type.equalsIgnoreCase("animal"))
        {
            if (size == "no")
            {
                guess = "squirrel";
            }
            else
            {
                guess = "moose";
            }
        }

        else if (type.equalsIgnoreCase("vegetable"))
        {
            if (size == "no")
            {
                guess = "carrot";
            }
            else
            {
                guess = "watermelon";
            }
        }

        else if (type.equalsIgnoreCase("mineral"))
        {
            if (size == "no")
            {
                guess = "paper clip";
            }
            else
            {
                guess = "Camero";
            }
        }

        if (guess == "")
        {
            System.out.println("The answers provided are not valid. Please try again.");
        }

        else
        {
            System.out.println("My guess is that you are thinking of a " + guess + ".");
            System.out.println("I would ask you if I'm right, but I don't actually care.");
        }
  }
}

问题是程序不关心嵌套if语句中的比较。控制总是转到else并打印出那个。

Answer 1

当您想要比较字符串时，您需要使用 .equals（）方法，或者在这种情况下忽略大小写 .equalsIgnoreCase（）

尝试下面的代码，您会发现它运行正常。

import java.util.Scanner;

public class TwentyQuestions {
public static void main ( String[] args )
{
    Scanner keyboard = new Scanner(System.in);

    String type, size, guess = "";

    System.out.println("TWO QUESTIONS!");
    System.out.println("Think of an object, and I'll try to guess it.");
    System.out.println("");

    System.out.println("Question 1) Is it animal, vegetable or mineral?");
    System.out.print("> ");
    type = keyboard.next();
    System.out.println("");

    System.out.println("Question 2) Is it bigger than a breadbox?");
    System.out.print("> ");
    size = keyboard.next();
    System.out.println("");

    if (type.equalsIgnoreCase("animal"))
    {
        if (size.trim().equalsIgnoreCase("no"))
        {
            guess = "squirrel";
        }
        else 
        {
            guess = "moose";
        }
    }

    else if (type.equalsIgnoreCase("vegetable"))
    {
        if (size.trim().equalsIgnoreCase("no"))
        {
            guess = "carrot";
        }
        else
        {
            guess = "watermelon";
        }
    }

    else if (type.equalsIgnoreCase("mineral"))
    {
        if (size.trim().equalsIgnoreCase("no"))
        {
            guess = "paper clip";
        }
        else
        {
            guess = "Camero";
        }
    }

    if (guess == "")
    {
        System.out.println("The answers provided are not valid. Please try again.");
    }

    else
    {
        System.out.println("My guess is that you are thinking of a " + guess + ".");
        System.out.println("I would ask you if I'm right, but I don't actually care.");
    }
  }
}

二十个问题 - 按行为编程

1 个答案: