创建一个数组列表(Creating an Array List)

我想利用我目前的计划，在main方法的方法了侧分离averging功能。 我想用扫描仪抓起号码存储到一个数组列表，然后用我的平均数方法，以便抓住那些数量和平均数字加在一起。 然后输出平均代替当前的System.out.println您的平均值是的..

请帮我说明这一点。 我无法理解这一切是如何走到一起。

import java.util.Scanner;

class programTwo {

public static void main (String[] args) {
    Scanner scan = new Scanner(System.in);
    double sum = 0;
    int count = 0;
    System.out.println ("Enter your numbers to be averaged:");
    String inputs = scan.nextLine();

    while (!inputs.contains("q")) {
        Scanner scan2 = new Scanner(inputs); // create a new scanner out of our single line of input

         {
            sum += scan2.nextDouble();
            count += 1;
            System.out.println("Please enter another number or press Q for your average");
        } 

        if(count == 21)
        {
            System.out.println("You entered too many numbers! Fail.");
            return;
        }
        inputs = scan.nextLine();
    }
    System.out.println("Your average is: " + (sum/count));
}
}

Answer 1:

//added an import here
import java.util.ArrayList;
import java.util.Scanner;

class programTwo
{
    //main difference is the average calculation is done within a method instead of main
    public static void main( String[] args )
    {
        Scanner scan = new Scanner(System.in);
        ArrayList<Double> myArr = new ArrayList<Double>();
        double sum = 0;
        int count = 0;
        System.out.println("Enter a number to be averaged:");
        String inputs = scan.nextLine();

    while (!inputs.contains("q")) //input until user no longer wants to give input
    {

        if (count == 21)
        {
            break; //this command here jumps out of the input loop if there are 21
        }

        Scanner scan2 = new Scanner(inputs); // create a new scanner out of our single line of input
        myArr.add(scan2.nextDouble()); //simply adding to the array list
        count += 1;
        System.out.println("Please enter another number or press Q for your average");

        inputs = scan.nextLine();
    }
    Double average = calculate_average(myArr); //go to method calculate average, expect a double to be returned
    System.out.println("Your average is: " + average); 
}

private static Double calculate_average( ArrayList<Double> myArr ) //method definition
{
    Double Sum = 0.0; 
    for (Double number: myArr) //for loop that iterates through an array list
    {
        Sum += number; //add all the numbers together into a sum
    }
    return Sum / myArr.size(); //return the sum divided by the number of numbers in the array list
}
}

这应该帮助。 祝您好运:)

Answer 2:

Average avg = new Average();

... avg.add(scan2.nextDouble());


System.out.println("Your average is: " + Average.result());


public class Average {
    void add(double x) { ... }
    double result() { ... }
}

思考了，我留给你的落实。

Answer 3:

下面是一些示例代码

private static void hoot(List<Double> kapow)
{
    ... do all the stuffs
}

public static void main(final String[] arguments)
{
    List<Double> blam = new ArrayList<Double>();
    blam.add(1.1);
    blam.add(1.2);
    blam.add(1.3);

    hoot(blam);
}

文章来源: Creating an Array List