If/else語句

Question

我前幾天剛開始使用java。我目前正在遵循這個'課程'http://programmingbydoing.com。還沒有遇到過任何問題，但但我現在停留在任務32

繼承人到目前爲止我的代碼（總是讓駝鹿輸出，而不是松鼠）：

import java.util.Scanner; 

公共類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");} 
} 
} 

提前致謝！也很想聽聽如何以更智能的方式提供代碼的技巧。要友好，請記住我剛剛開始！

編輯：好的，我採取了另一種方法。我的第一次嘗試真的很奇怪。謝謝您的幫助！

繼承人的工作代碼：

import java.util.Scanner; 

公共類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語句要設置動物爲true每次 if (animal = true){，而不是檢查它（ ==）

。 另外，對於字符串，您必須使用.equals()而不是==。