Question

import java.util.Scanner;

public class Main extends Hashmap{

    public static void main(String[] args) {
        Hashmap hm = new Hashmap();
        int x=0;
        Scanner input = new Scanner(System.in);
        do{
            System.out.print("Enter any integer value between 1 to 12: ");
            x = input.nextInt();
        }while(x<=0 || x>12);
        Scanner sc = new Scanner(System.in);
        //int number;


       do {
           while (!sc.hasNextInt())
           {
            System.out.println("That's not a number!");
            sc.next();
           }
            x = sc.nextInt();
           }while(x>=0);

        String month = hm.getEntry(x);
        System.out.println(month);




}
    }

这里我需要限制用户输入字母。但它不起作用。请帮忙......

Answer 1

首先，再次查看polygenelubricants comprehensive answer您的问题。我很确定，他在例3中为你解决了这个问题。

然后，作为用户界面的替代设计：接受任何用户输入，验证输入，如果输入不正确，请提供有用的消息并要求用户再次输入值。这实现起来要容易得多，用户也应该对此感到满意。

Answer 2

public static void main(String[] args) {
    HashMap<Integer, String> hm = new HashMap<Integer, String>();
    /**
     * Populate hashmap.. Your logic goes here
     */
    Scanner sc = new Scanner(System.in);
    int x;
    System.out.println("Enter a number between 1 and 12");
    do {
        while (!sc.hasNextInt()) {
            System.out.println("That's not a number! Enter a number between 1 and 12");
            sc.next();
        }
        x = sc.nextInt();
        String month = hm.get(x);
        System.out.println("The corresponding month is " + month);
    } while (x >= 0);

}

我认为这是你想要实现的目标..

我已经应用了一个不允许使用字母的检查。但它不起作用

2 个答案: