用用户输入计算平均值 [英] calculate average with user input

问题描述

我正在编写一个程序来计算用户输入的平均值.

I'm writing a program to calculate average with user input.

import java.util.Scanner;
public class mean
{   
    static Scanner input = new Scanner (System.in);
    public static void main (String[] args)
    {
    double i;
    double sum = 0;
    int count = 0;
    do
    {
        System.out.println("input");
        i = input.nextDouble();
        sum = sum + i;
        count++;
    }while (i != 0);
    System.out.println("sum is " + sum + " count is " + (count - 1));
    System.out.println("average is " + sum / (count - 1));
}
}

在这里，如果我输入0，它将进行计算.但是如果列表中有0.有人可以指导我好一阵子吗?

here if I input 0, it will calculate. but if there is 0s in the list. can somebody guide me a great while condition?

推荐答案

您可以询问扫描程序，该扫描程序正在读取的下一个令牌是否为double，如果不是，则中断.下面的示例:

You could ask the scanner whether or not the next token that the scanner is reading is a double and break if it isn't. Example below:

import java.util.Scanner;
public class mean
{   
    static Scanner input = new Scanner (System.in);
    public static void main (String[] args)
    {
    double i;
    double sum = 0;
    int count = 0;
    while(input.hasNextDouble())
    {
        System.out.println("input");
        i = input.nextDouble();
        sum = sum + i;
        count++;
    }
    System.out.println("sum is " + sum + " count is " + (count));
    System.out.println("average is " + sum / (count));
}
}

如果用户输入非数字字符(例如，非'+'，'-'，0-9，'.'等)，则循环将中断，因为input.hasNextDouble()将返回false.

If the user inputs a non-digit character (e.g. not '+', '-', 0-9, '.', etc.), the loop will break because input.hasNextDouble() will return false.

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