java - 求最后一列的平均值

Question

所以我需要程序打印出每周平均气温的平均值，但我找不到如何做到这一点的解决方案。目前，我有一列将一周的平均气温打印为 System.out.print ，所以它不在二维数组中，但现在我需要找到这些平均值的平均值。我尝试使用 System.out.print(average/4);找到平均值，但打印出来的数字不正确。我应该如何为此编写代码？

import java.text.DecimalFormat;
import java.util.Scanner;

public class TwoDimArray {

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

        // 1) Declare and allocate Storage
        //Each day name is assigned to the array as a String so each name must be enclosed in apostrophes and each string must be separated by commas.
        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
        double[][] Temperature = new double[4][7];

        // 2) Populate Array
        for (int i = 0; i < Temperature.length; i++) {
            for (int j = 0; j < Temperature[0].length; j++) {
                //days[j] will print the proper day and "(i+1)" will print the proper day of the week
                System.out.print("Enter " + days[j] + " Temperature " + "for Week " + (i + 1) + ": " + "    ");
                Temperature[i][j] = scan.nextDouble();
            }

        }
        System.out.println();
        System.out.println("              Weekly Temperature Report ");
        System.out.println("Mon     Tue     Wed     Thurs    Fri    Sat     Sun    Average");

        double columnTotal, average;
        // 4) Output Array

        for (int i = 0; i < Temperature.length; i++) {
            System.out.println();
            columnTotal = 0;
            for (int j = 0; j < Temperature[0].length; j++) {
                System.out.print(Temperature[i][j] + "\t");
                columnTotal += Temperature[i][j];
            }
            average = columnTotal / 7;
            System.out.println(average);
        }

        System.out.println();
        System.out.println("------------------------------------------------------------------");
        int avg;
        for (int i = 0; i < Temperature[0].length; i++) {
            columnTotal = 0;
            avg = 0;
            for (int j = 0; j < Temperature.length; j++) {
                columnTotal = columnTotal + Temperature[j][i];

            }
            System.out.print((columnTotal / 4) + "    ");
            System.out.print(average / 4);

        }
    }
}

Answer 1

确定对您的代码进行以下更改

1. 声明平均值数组average[] = new double[Temperature.length];

2. 替换此 average = columnTotal / 7 ; System.out.println(average);有了这个

   average[i] = columnTotal / 7 ; System.out.println(average[i]);所以我正在做什么将平均值存储在数组中。您将平均值存储在一个简单的变量中，该变量被一次又一次地覆盖，直到循环结束

3. 最后将代码的最后一部分替换为

   列总数 = 0;

   for (int i = 0; i < average.length; i++) {
           columnTotal = columnTotal +average[i];
       }
       System.out.print((columnTotal / 4) + "    ");
   

最后你的代码将如下所示

import java.text.DecimalFormat;
import java.util.Scanner;

public class TwoDimArray {

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

        // 1) Declare and allocate Storage
        //Each day name is assigned to the array as a String so each name must be enclosed in apostrophes and each string must be separated by commas.
        String[] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
        double[][] Temperature = new double[4][7];

        // 2) Populate Array
        for (int i = 0; i < Temperature.length; i++) {
            for (int j = 0; j < Temperature[0].length; j++) {
                //days[j] will print the proper day and "(i+1)" will print the proper day of the week
                System.out.print("Enter " + days[j] + " Temperature " + "for Week " + (i + 1) + ": " + "    ");
                Temperature[i][j] = scan.nextDouble();
            }

        }
        System.out.println();
        System.out.println("              Weekly Temperature Report ");
        System.out.println("Mon     Tue     Wed     Thurs    Fri    Sat     Sun    Average");

        double columnTotal, average[] = new double[Temperature.length];
        // 4) Output Array

        for (int i = 0; i < Temperature.length; i++) {
            System.out.println();
            columnTotal = 0;
            for (int j = 0; j < Temperature[0].length; j++) {
                System.out.print(Temperature[i][j] + "\t");
                columnTotal += Temperature[i][j];
            }
            average[i] = columnTotal / 7;
            System.out.println(average[i]);
        }

        System.out.println();
        System.out.println("------------------------------------------------------------------");

        columnTotal = 0;
        for (int i = 0; i < average.length; i++) {
                columnTotal = columnTotal +average[i];
            }
            System.out.print((columnTotal / 4) + "    ");
            //System.out.print(average/4);

        }
    }