Question

我试图让骰子滚动，我在某处添加循环时遇到了一些困难，所以程序在一次滚动后就不会退出。我想询问用户是否要滚动，然后通过说＆＃34; y来滚动。＆＃34;我想通过询问用户相同的问题结束该程序，但它以＆＃34; n＆＃34;

结束

/*
    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

您必须在以下表达式后阅读输入：

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

接收用户输入电话：input.nextLine();。此后循环，输入为"y"。如果用户输入不等于"y"，while-loop将被终止。

只要条件为while(condition)

，true循环就会被执行

当特定条件为真时，while语句会不断执行一个语句块。 The while and do-while Statements

例如，请考虑以下代码：

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();
    }
}

要了解有关while和Do-while机制的更多信息，请访问此toturial

（*）要了解在调用nextInt（）之后使用nextLine（），请访问Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo() methods

Answer 2

锻炼是一个非常好的选择。另一种方法是使用带开关的while循环或最好使用IF / ELSE IF语句。也许就像下面这样。这只是一个建议。

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;
   }
}

我试图在我的骰子滚动计划中添加一个循环

2 个答案: