Question

我目前正在用Java编程创建“Nim”游戏。但是，我完全迷失了如何修改我的程序以使用户只输入整数，如果他们输入任何其他内容，请他们输入一个整数。

import java.util.Scanner;

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

        int noEntered;

        int firstPile = 3;
        int secondPile = 4;
        int thirdPile = 5;

        int next = 1;

        int choose;

        do 
        {
            if (next % 2 == 1) 
            {
                System.out.print("Player 1 - choose bag: ");
                choose = scanner.nextInt();

                if (choose == 1) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    firstPile = firstPile - noEntered;
                    System.out.println("Bag Status: " + + firstPile + ", " + secondPile + ", " 
                    + thirdPile);
                } 
                else if (choose == 2) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    secondPile = secondPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } 
                else if (choose == 3) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    thirdPile = thirdPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }        
            }
            else
            {
                System.out.print("Player 2 - choose bag: ");
                choose = scanner.nextInt();
                if (choose == 1) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    firstPile = firstPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }
                else if (choose == 2)
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    secondPile = secondPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } 
                else if (choose == 1) 
                {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = scanner.nextInt();
                    thirdPile = thirdPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }              
            }
            next++;
        } 
        while (firstPile != 0 && secondPile != 0 && thirdPile != 0);

        if (next % 2 == 1) 
        {
            System.out.println("Game Over - Player 1 wins");
        } 
        else if (next % 2 == 0)
        {
            System.out.println("Game Over - Player 2 wins");
        }
    }
}

有任何帮助吗？感谢。

Answer 1

像这样使用try和catch()，

try{
        System.out.print("Player 1 - choose bag: ");
        choose = scanner.nextInt();
}catch(InputMismatchException exception)
{
  System.out.println("This is not an integer");
}

UPDATE:

import java.util.Scanner;

public class Nim 
{
  public static void main(String[] args) 
  {
   try{
    Scanner scanner = new Scanner(System.in);
    int noEntered;
    int firstPile = 3;
    int secondPile = 4;
    int thirdPile = 5;

    int next = 1;

    int choose;

    do 
    {
        if (next % 2 == 1) 
        {
            System.out.print("Player 1 - choose bag: ");
            choose = scanner.nextInt();

            if (choose == 1) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                firstPile = firstPile - noEntered;
                System.out.println("Bag Status: " + + firstPile + ", " + secondPile + ", " 
                + thirdPile);
            } 
            else if (choose == 2) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                secondPile = secondPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            } 
            else if (choose == 3) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                thirdPile = thirdPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            }        
        }
        else
        {
            System.out.print("Player 2 - choose bag: ");
            choose = scanner.nextInt();
            if (choose == 1) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                firstPile = firstPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            }
            else if (choose == 2)
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                secondPile = secondPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            } 
            else if (choose == 1) 
            {
                System.out.print("Now choose no. of tokens: ");
                noEntered = scanner.nextInt();
                thirdPile = thirdPile - noEntered;
                System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                        + thirdPile);
            }              
        }
        next++;
    } 
    while (firstPile != 0 && secondPile != 0 && thirdPile != 0);

    if (next % 2 == 1) 
    {
        System.out.println("Game Over - Player 1 wins");
    } 
    else if (next % 2 == 0)
    {
        System.out.println("Game Over - Player 2 wins");
    }
   }catch(InputMismatchException exception){
        System.out.println("Given input is not a number");
      }
   }
  }

Answer 2

在你的问题模式中，匹配对于避免使用try catch块进行异常捕获和处理非常有用，你可以定义一个模式来识别整数。

static Pattern PATTERN = Pattern.compile( "^(-?0|-?[1-9]\\d*)" );

验证整数。

 public static boolean isInteger( String value ) {
    return value != null && PATTERN.matcher( value ).matches();
  }

使用方法获取输入并验证输入是否仅为整数否则显示消息，如＆＃34;请输入有效的整数＆＃34;并等待下一个有效输入。

public static Integer getIntInput(Scanner scanner){
        String sentanse=scanner.next();
        if(isInteger(sentanse)){
            System.out.println("number "+sentanse);
          return Integer.parseInt(sentanse);
        }else{
            System.out.println("Please enter valid Integer");
           return getIntInput(scanner);
        }
}

要查看结果，请修改如下代码

public class Nim {

    static Pattern PATTERN = Pattern.compile("^(-?0|-?[1-9]\\d*)");

    public static boolean isInteger(String value) {
        return value != null && PATTERN.matcher(value).matches();
    }

    public static Integer getIntInput(Scanner scanner) {
        String sentanse = scanner.next();
        if (isInteger(sentanse)) {
            System.out.println("number " + sentanse);
            return Integer.parseInt(sentanse);
        } else {
            System.out.println("Please enter valid Integer");
            return getIntInput(scanner);
        }
    }

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

        int noEntered;

        int firstPile = 3;
        int secondPile = 4;
        int thirdPile = 5;

        int next = 1;

        int choose;

        do {
            if (next % 2 == 1) {
                System.out.print("Player 1 - choose bag: ");
                choose = getIntInput(scanner);

                if (choose == 1) {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = getIntInput(scanner);
                    firstPile = firstPile - noEntered;
                    System.out.println("Bag Status: " + +firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } else if (choose == 2) {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = getIntInput(scanner);
                    secondPile = secondPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } else if (choose == 3) {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = getIntInput(scanner);
                    thirdPile = thirdPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }
            } else {
                System.out.print("Player 2 - choose bag: ");
                choose = getIntInput(scanner);
                if (choose == 1) {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = getIntInput(scanner);
                    firstPile = firstPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } else if (choose == 2) {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = getIntInput(scanner);
                    secondPile = secondPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                } else if (choose == 1) {
                    System.out.print("Now choose no. of tokens: ");
                    noEntered = getIntInput(scanner);
                    thirdPile = thirdPile - noEntered;
                    System.out.println("Bag Status: " + firstPile + ", " + secondPile + ", "
                            + thirdPile);
                }
            }
            next++;
        } while (firstPile != 0 && secondPile != 0 && thirdPile != 0);

        if (next % 2 == 1) {
            System.out.println("Game Over - Player 1 wins");
        } else if (next % 2 == 0) {
            System.out.println("Game Over - Player 2 wins");
        }


}

希望这可以帮助您解决问题。

Answer 3

你可以使用 scanner.hasNextInt（）找出是否有int

Answer 4

public static int validateNumber () { 
    try {
        return scanner.nextInt();
    } catch (InputMismatchException e ) {
         scanner.next();
        System.out.println("not a number");
        return 0 ;
    }
}

Answer 5

使用

if(scanner.hasNextInt())

这里参考： [http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#hasNextInt()][1]

如果输入除整数之外的任何内容，请要求用户仅输入整数

5 个答案: