我想添加一個循環到我的骰子滾動程序

Question

我想要得到一個骰子滾動發生，我有一些困難添加一個循環某處，所以程序不會退出一個滾動後。我想詢問用戶是否要滾動，並通過說「y」。我想通過詢問用戶同樣的問題，以結束該程序，但它與「N」

/* 
    Natasha Shorrock 
    Assignmnt A6 
    11/07/16 
    */ 
    package diceroller; 
    import java.util.Random; 
    import java.util.Scanner; 

    public class DiceRoller { 
     public static void main(String []args) { 
      System.out.println(" Do you want to roll the dice? "); 
      Random dice = new Random(); 
      Scanner input = new Scanner(System.in); 
      int faces; 
      int result; 

      System.out.println("Dice Roller\n"); 
      System.out.println("How many faces does the dice have?"); 
      faces = input.nextInt(); 
      result = dice.nextInt(faces) + 1; 
      System.out.println("\nThe dice rolled a " + result); 
     }//Dice Roller 
    }//class DiceRoller 

Answer 1

您必須閱讀下面的表達式後輸入端：

System.out.println(" Do you want to roll the dice? "); 

要接收用戶輸入致電：input.nextLine();。此後循環，而輸入是"y"。如果用戶輸入不等於"y"，則while-loop終止。

的while(condition)循環，只要條件true

而特定條件爲真while語句連續執行語句塊excuted。 The while and do-while Statements

例如考慮這個代碼：

public static void main(String[] args) { 
    Random dice = new Random(); 
    Scanner input = new Scanner(System.in); 
    System.out.println("Do you want to roll the dice? (y: yes/q: to quit)"); 
    String answer = input.nextLine(); // reading the input 

    // we check if the answer is equals to "y" to execute the loop, 
    // if the answer is not equals to "y" the loop is not executed 
    while ("y".equals(answer)) { 
     System.out.println("Dice Roller"); 
     System.out.println("How many faces does the dice have?"); 
     int faces = input.nextInt(); 
     int result = dice.nextInt(faces) + 1; 
     input.nextLine(); // to read the newline character (*) 
     System.out.println("The dice rolled a " + result); 
     System.out.println("Do you want to roll the dice? (y: yes/q: to quit)"); 
     answer = input.nextLine(); 
    } 
} 

要了解更多有關而和do-while機制，請訪問該toturial

（*）要了解使用nextLine的（）呼叫nextInt（）後請訪問Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo() methods

Answer 2

一個do-while是一個很好的選擇。另一種做法是使用帶開關的while循環或最好是IF/ELSE IF語句。也許像下面的東西。這只是一個建議。

boolean checkForExit = false; 
while(checkForExit != true) { //while checkForExit does not equal true (therefore false) continue.. 

    System.out.println("Do you want to roll the dice?"); 
    String answer = input.next(); //get char input from user. 

    if(answer.toLowerCase().equals("y")) { //if 'y' then do this 
    //ask user for number of faces on dice and roll 
    } else { // otherwise end the program 
     //set isTrue to true to exit while loop. ends program 
     isTrue = true; 
    } 
}