If/else语句

Question

我前几天刚开始使用java。我目前正在遵循这个'课程'http://programmingbydoing.com。还没有遇到过任何问题，但但我现在停留在任务32

继承人到目前为止我的代码（总是让驼鹿输出，而不是松鼠）：

import java.util.Scanner; 

公共类TwoQuestion32 {

public static void main(String[] args) { 
    boolean animal, vegetable, mineral, smallerthan; 

    String whatIsIt, biggerThan; 
    Scanner keyboard = new Scanner(System.in); 


    System.out.println("Hello and welcome, i've got 2 questions for you!"); 
    System.out.println("Think of an object and i'll try to guess it"); 
    System.out.println(); 
    System.out.println("Question 1) Is it an animal, vegetable or mineral?"); 
    System.out.print(">"); 
    whatIsIt = keyboard.nextLine(); 

    if (whatIsIt == "animal") 
      animal = true; 
      if (whatIsIt == "vegetable") 
      vegetable = true; 
      if (whatIsIt == "mineral") 
      mineral = true; 


    System.out.println("Question 2) Is it bigger than a breadbox?"); 
    System.out.print(">"); 
     biggerThan = keyboard.nextLine(); 
      if (biggerThan == "yes") 
      smallerthan = false; 
      if (biggerThan == "no"){ 
      smallerthan = true;} 


      System.out.print("My guess is that you are thinking of a "); 
     if (animal = true){ 
      if (smallerthan = true) 
       System.out.println("squirrel"); 
     }else { 
       System.out.println("moose");} 
} 
} 

提前致谢！也很想听听如何以更智能的方式提供代码的技巧。要友好，请记住我刚刚开始！

编辑：好的，我采取了另一种方法。我的第一次尝试真的很奇怪。谢谢您的帮助！

继承人的工作代码：

import java.util.Scanner; 

公共类Questions32 {

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


    String whatIsIt, whatIsIt2; 
    String animal = "animal"; 
    String mineral = "mineral"; 
    String vegetable = "vegetable"; 
    String bigger = "yes"; 
    String smaller = "no"; 


    System.out.println("Hello and welcome, i've got 2 questions for you!"); 
    System.out.println("Think of an object and i'll try to guess it"); 
    System.out.println(); 
    System.out.println("Question 1) Is it an animal, vegetable or mineral?"); 
    System.out.print(">"); 
    whatIsIt = keyboard.nextLine(); 

    System.out.println("Question 2) Is it bigger than a breadbox?"); 
    System.out.print(">"); 
     whatIsIt2 = keyboard.nextLine(); 

    if (whatIsIt.equalsIgnoreCase(animal)){ 
     if (whatIsIt2.equalsIgnoreCase(bigger)){ 
      System.out.println("My guess is that you are thinking of a moose"); 
     }else{ System.out.println("My guess is that you are thinking of a squirrel"); 
     } 
    } 

    if (whatIsIt.equalsIgnoreCase(vegetable)){ 
     if (whatIsIt2.equalsIgnoreCase(bigger)){ 
      System.out.println("My guess is that you are thinking of a melon"); 
     }else{ System.out.println("My guess is that you are thinking of a carrot"); 
     } 
    } 

    if (whatIsIt.equalsIgnoreCase(mineral)){ 
     if (whatIsIt2.equalsIgnoreCase(bigger)){ 
      System.out.println("My guess is that you are thinking of a Camaro"); 
     }else{ System.out.println("My guess is that you are thinking of a paper clip"); 
     } 
    } 
    System.out.println("I would ask you if I'm right, but I dont actually care."); 

    } 


} 

Answer 1

在您的if语句要设置动物为true每次 if (animal = true){，而不是检查它（ ==）

。 另外，对于字符串，您必须使用.equals()而不是==。