Question

我有两个程序：

Score.java设置为执行以下操作：

从键盘读取分数并打印其平均值。
分数将为数字，可能包含小数部分。

例如，分数可能是8.73或某些分数。不同的比赛将有不同数量的评委。在用户键入“完成”之前，它将继续询问和读取分数。然后该程序将打印总分，分数和平均分数。然后程序将提示用户查看是否还有其他参赛者。如果有再次开始提示分数。如果没有，则退出程序。“我设置为在输入”N“时停止程序，并设置为在输入”Y“后将未来的条目添加到计算中。

import java.util.Scanner;

// This is the Score program
// Written by me

public class Score
{
    public static void main(String args[])
    {
        Scanner game = new Scanner(System.in);
        double num = 0.0;
        double sum = 0.0;
        int cnt = 0;

        while (true)
        {
            System.out.println("Enter as many non-negative integers as you like ");
            System.out.println("one at a time and I will find the average");
            System.out.println("Enter done to stop entering numbers");

            System.out.print("enter number: ");
            String ans = game.next();
            while (!ans.equals("done"))
            {
                num = Double.parseDouble(ans);
                sum = sum + num;
                cnt = cnt + 1;

                System.out.print("enter number: ");
                ans = game.next();
            }
            System.out.println(cnt);
            System.out.println(sum);

            System.out.println("Total Score " + sum + " count scores " + cnt + " avg score " + sum / cnt);

            System.out.println("Enter another contestant (Y/N)?");
            String str = game.next();
            if (!str.equals("Y"))
                break;
        }
    }
}

虽然上述过程有效，但在输入“Y”以添加更多分数后，我无法让第二个程序Olympic.java正常工作。相反，它开始一个全新的平均值计算，而不是添加到以前的计算中：

import java.util.Scanner;

// This is the Olympic program
// Written by me

public class Olympic
{
    public static void main(String args[])
    {
        Scanner game = new Scanner(System.in);
        double num = 0.0;
        double sum = 0.0;
        int cnt = 0;
        double highscore = Double.MAX_VALUE;
        double lowscore = Double.MIN_VALUE;

        while (true)
        {
            System.out.println("Enter as many non-negative integers as you like ");
            System.out.println("one at a time and I will find the average");
            System.out.println("Enter done to stop entering numbers");

            System.out.print("enter number: ");
            String ans = game.next();
            lowscore = game.nextDouble();
            highscore = game.nextDouble();
            while (!ans.equals("done"))
            {
                num = Double.parseDouble(ans);
                sum = (sum + num) - lowscore - highscore;
                cnt = cnt + 1;

                System.out.print("enter number: ");
                if (num > highscore)
                {
                    highscore = num;
                }
                if (num < lowscore)
                {
                    lowscore = num;
                }
                ans = game.next();
            }
            System.out.println("Throwing out low score " + lowscore + " and high score " + highscore);
            System.out.println("Total Score " + sum + " count scores " + cnt + " avg score " + sum / cnt);

            System.out.println("Enter another contestant (Y/N)?");
            String str = game.next();
            if (!str.equals("Y"))
                break;
        }
    }
}

Answer 1

所以我做了一个非常快速的测试

public static void main(String[] args) {

    Scanner game = new Scanner(System.in);

    while (true) {

        System.out.println("Enter another contestant (Y/N)?");
        String str = game.next();
        if (!str.equalsIgnoreCase("Y")) {
            break;
        }
    }

    System.out.println("I'm free");

}

这将退出。

关于你的第二个问题。我认为你的逻辑有点偏差。你可以试试像......

Scanner game = new Scanner(System.in);

double num = 0;
double sum = 0;
int cnt = 0;

while (true) {
    System.out.println("Enter as many non-negative integers as you like ");
    System.out.println("one at a time and I will find the average");
    System.out.println("Enter done to stop entering numbers");

    double lowscore = Double.MAX_VALUE;
    double highscore = 0;

    System.out.print("enter number: ");
    String ans = game.next();
    while (!ans.equals("done")) {

        num = Double.parseDouble(ans);

        lowscore = Math.min(lowscore, num);
        highscore = Math.max(highscore, num);

        sum += num;
        cnt++;

        System.out.print("enter number: ");
        if (num > highscore) {
            highscore = num;
        }
        if (num < lowscore) {
            lowscore = num;
        }
        ans = game.next();
    }

    sum -= lowscore;
    sum -= highscore;

    System.out.println("Throwing out low score " + lowscore + " and high score " + highscore);
    System.out.println("Total Score " + sum + " count scores " + cnt + " avg score " + sum / cnt);

    System.out.println("Enter another contestant (Y/N)?");
    String str = game.next();
    if (!str.equalsIgnoreCase("Y")) {
        break;
    }
}

这将输出......

Enter as many non-negative integers as you like 
one at a time and I will find the average
Enter done to stop entering numbers
enter number: 1
enter number: 2
enter number: 3
enter number: 4
enter number: 5
enter number: 6
enter number: 7
enter number: 8
enter number: 9
enter number: 10
enter number: done
Throwing out low score 1.0 and high score 10.0
Total Score 44.0 count scores 10 avg score 4.4
Enter another contestant (Y/N)?
y
Enter as many non-negative integers as you like 
one at a time and I will find the average
Enter done to stop entering numbers
enter number: 1
enter number: 12
enter number: 13
enter number: 14
enter number: 15
enter number: 16
enter number: 17
enter number: 18
enter number: 19
enter number: 20
enter number: done
Throwing out low score 1.0 and high score 20.0
Total Score 168.0 count scores 20 avg score 8.4
Enter another contestant (Y/N)?
n

关于你的例外情况。使用Scanner.nextDouble时，如果输入不能解析为double，则会抛出异常。你需要在你认为合适的情况下处理这种情况......

“输入另一个数字（Y / N？）”过程从“Y”开始而不是继续

1 个答案: