Question

我目前无法通过用户输入结束我的程序。我现在只能在用户输入20个数字时结束。我想要它做的是，如果用户输入的数字超过100，它应该停止程序并显示直方图和数字，以显示用户每次输入数字的次数。对不起，如果我没有任何意义，如果需要进一步的信息，我会更新这篇文章。这是我的代码。

import java.util.Scanner;

public class Marks {
    /**
    * @param args the command line arguments
    */
    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int[] array = new int[23];
        int num = 0;
        int count = 0;
        int total = 0;

        System.out.println ("Enter students marks in the range 0 to 100\n");

        for (count = 0; count <= 20; count++)
        {
            System.out.println ("Enter a number:");
            num = scan.nextInt();
            while (num < 0 || num > 100)
            {
                System.out.println ("Invalid number. Enter a valid number.");
                num = scan.nextInt();
            }
            array[count] = num;
           total=count;
        }
        System.out.println ("How many times a number between 0-100 occur.");

        String[] asterisk = {"0- 29   | ", "30- 39  | ","40- 69  | ", "70- 100 | "}; //4 strings

        for (count = 0; count <= 20; count++)
        {
            num=array[count];
            if (num <=29) asterisk [0] +="*";
            else if (num <=39) asterisk[1] +="*";
            else if (num <=69) asterisk[2] +="*";
            else if (num <=100) asterisk[3] +="*";
        }
        for (count =0;count < 4;count++)
            System.out.println(asterisk[count]);
        System.out.println("The total amount of students is " + total);
    }
}

Answer 1

当用户进行交互时，您可以编写

System.exit(0);

Answer 2

您的代码中存在错误

这是您更新的代码

public class Marks {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {

    Scanner scan = new Scanner(System.in);

    int[] array = new int[23];
    int num = 0;
    int count = 0;
    int total = 1;

    System.out.println ("Enter students marks in the range 0 to 100\n");

        loop: for (count = 0; count <= 20; count++) {
            System.out.println("Enter a number:");
            num = scan.nextInt();
            if (num < 0 || num > 100) {
                break loop;

            }
            array[count] = num;
            total = count+1;
        }
    System.out.println ("How many times a number between 0-100 occur.");

    String[] asterisk = {"0- 29   | ", "30- 39  | ","40- 69  | ", "70- 100 | "}; //4 strings

    for (count = 1; count <= total; count++)
    {
        num=array[count];
        if (num >=0 && num<=29) asterisk [0] +="*";
        else if (num>29 && num<=39) asterisk[1] +="*";
        else if (num>39 && num <=69) asterisk[2] +="*";
        else if (num >69 && num <=100) asterisk[3] +="*";
    }
    for (count =0;count < 4;count++)
        System.out.println(asterisk[count]);
    System.out.println("The total amount of students is " + total);
}
}

这是输出

Enter students marks in the range 0 to 100

Enter a number:
1

Enter a number:
10
Enter a number:
50
Enter a number:
111
How many times a number between 0-100 occur.
0- 29   | **
30- 39  | 
40- 69  | *
70- 100 | 
The total amount of students is 3

Answer 3

else if (num >100) System.exit(0);

这应该不行吗？

Answer 4

您是否尝试过使用System.exit（0）？

Answer 5

你应该检查如何使用while循环。

而不是for循环。并有一些像

的声明

while( userinput < 100)
{
 //insert code here
}

Answer 6

在匹配条件下，您可以使用System.exit（0）

if(matchCondition) {
    System.exit(0);
}

Answer 7

这个修复......快速而肮脏：

    for (count = 0; count <= 20; count++)
    {
        System.out.println ("Enter a number:");
        num = scan.nextInt();
        while (num < 0 || num > 100)
        {
            if (num > 100) {
               count = 20;
               break;
            }

            System.out.println ("Invalid number. Enter a valid number.");
            num = scan.nextInt();

        }
        array[count] = num;
       total=count;
    }

但我不推荐这种方法。请考虑使用while循环。

如何使用java中的用户输入结束程序？

7 个答案: