如何在循环中找到所有测试分数的最高，最低和平均值？

Question

下午好，或者无论何时阅读。 我试图弄清楚如何才能找到用户输入的最低，最高和平均测试分数。 我有一个循环来跟踪前哨值，在我的情况下为999。因此，当用户输入999时，它退出循环。 通过检查用户输入的数字是否大于100或小于0，我还具有某种程度的数据验证。 但是，我的问题是，我该如何实现一种获得此代码的方式，以查找用户输入所需的值。 我的代码如下：

import java.util.Scanner;
public class TestScoreStatistics 
{

    public static void main(String[] args) 
    {
        Scanner scn = new Scanner(System.in);
        int testScore;
        double totalScore = 0;
        final int QUIT = 999;
        final String PROMPT = "Enter a test score >>> ";
        int lowScore;
        int highScore;
        String scoreString = "";
        int counter = 0;

        System.out.print(PROMPT);
        testScore = scn.nextInt();

        while (testScore != QUIT)
        {

            if (testScore < 0 || testScore > 100 )
            {
                System.out.println("Incorect input field");

            }
            else
            {
                scoreString += testScore + " ";
                counter++;
            }

            System.out.print(PROMPT);
            testScore = scn.nextInt();



        }
        System.out.println(scoreString);
        System.out.println(counter + " valid test score(s)");

    }

}

Answer 1

在保持代码几乎相同的同时，您可以这样做：

import java.util.Scanner;
public class TestScoreStatistics 
{

    public static void main(String[] args) 
    {
        Scanner scn = new Scanner(System.in);
        int testScore;
        double totalScore = 0;
        final int QUIT = 999;
        final String PROMPT = "Enter a test score >>> ";
        int lowScore = 100; //setting the low score to the highest score possible
        int highScore = 0; //setting the high score to the lowest score possible
        String scoreString = "";
        int counter = 0;

        System.out.print(PROMPT);
        testScore = scn.nextInt();

        while (testScore != QUIT)
        {

            if (testScore < 0 || testScore > 100 )
            {
                System.out.println("Incorect input field");

            }
            else
            {
                scoreString += testScore + " ";
                counter++;
                //getting the new lowest score if the testScore is lower than lowScore
                if(testScore < lowScore){
                    lowScore = testScore;
                }
                //getting the new highest score if the testScore is higher than highScore
                if(testScore > highScore){
                    highScore = testScore;
                }
                totalScore += testScore; //adding up all the scores
            }

            System.out.print(PROMPT);
            testScore = scn.nextInt();
         }
        double averageScore = totalScore / counter; //getting the average
     }

这将检查testScore是高于还是低于最高和最低分数。 该程序还将所有分数相加，然后除以计数器（即有多少个测试）以得到平均值。

Answer 2

这就是我要做的。

// defines your prompt
private static String PROMPT = "Please enter the next number> ";

// validation in a separate method
private static int asInteger(String s)
{
    try{
        return Integer.parseInt(s);
    }catch(Exception ex){return -1;}
}

// main method
public static void main(String[] args)
{

    Scanner scn = new Scanner(System.in);
    System.out.print(PROMPT);
    String line = scn.nextLine();

    int N = 0;
    double max = 0;
    double min = Integer.MAX_VALUE;
    double avg = 0;
    while (line.length() == 0 || asInteger(line) != -1)
    {
        int i = asInteger(line);
        max = java.lang.Math.max(max, i);
        min = java.lang.Math.min(min, i);
        avg += i;
        N++;

        // new prompt
        System.out.print(PROMPT);
        line = scn.nextLine();
    }
    System.out.println("max : " + max);
    System.out.println("min : " + min);
    System.out.println("avg : " + avg/N);
}

验证方法将（在其当前实现中）允许输入任何整数。 一旦输入了任何不能转换为数字的内容，它将返回-1，这将触发从主循环的中断。

主循环仅跟踪当前的运行总计（以计算平均值）以及到目前为止所看到的最大值和最小值。

退出循环后，这些值将简单地打印到System.out 。

Answer 3

用最少的代码更改：

public class Answer {

    public static void main(String[] args) {

        Scanner scn = new Scanner(System.in);
        int testScore;
        final int QUIT = 999;
        final String PROMPT = "Enter a test score >>> ";
        int maxScore = Integer.MIN_VALUE;
        int minScore = Integer.MAX_VALUE;
        double totalScore = 0;
        double avgScore = 0.0;
        int counter = 0;

        System.out.print(PROMPT);
        testScore = scn.nextInt();

        while (testScore != QUIT) {

            if (testScore < 0 || testScore > 100) {
                System.out.println("Incorect input field");

            } else {
                counter++;
                System.out.println("The number of scores you entered is " + counter);
                //test for minimum
                if(testScore < minScore) minScore = testScore;
                System.out.println("Current minimum score = " + minScore);
                //test for maximum
                if(testScore > maxScore) maxScore = testScore;
                System.out.println("Current maximum score = " + maxScore);
                //calculate average
                totalScore += testScore;
                avgScore = totalScore / counter;
                System.out.println("Current average score = " + avgScore);
            }

            System.out.print(PROMPT);
            testScore = scn.nextInt();

        }
    }
}