java使用Double。I/O中的parseDouble（）

Question

我试图编写一个程序，从用户那里获取一系列五个双字符串值，然后尝试使用Double.parseDouble()方法将这些字符串转换为双字符串。我遇到的问题是，在弹出下一个“Please enter a number”之前，我必须输入两个值。以下是我得到的结果：

Please enter a number 1: 4
3
Please enter a number 2: 5
4
Please enter a number 3: 3
4
Please enter a number 4: 5
6
Please enter a number 5: 4
2
The average is: 3.8 

这是我的密码：

import java.io.*;
import java.util.Scanner;

public class theman {
    public static void main(String[] args) throws IOException{

    // Variables
        int counter;
        int userEntries = 5;
        double sum = 0;


        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(isr);


    // Creating a new Scanner
        Scanner scanner = new Scanner(System.in);

    // Loop for the five entries    
        for (counter = 1; counter <= userEntries; counter++) {
            String input = "";
            System.out.print("Please enter a number " + counter + ": ");
            input = br.readLine();
            double number = Double.parseDouble(input);
            sum += scanner.nextDouble();
        }   

    // Print statements
        System.out.println("The average is: " + sum / userEntries);


    } // End of method header
} // End of class header

纠正此问题的最佳方法是什么？我假设这是因为sum += scanner.nextDouble();，但我需要它增加，所以我真的不能删除它

Answer 1

你已经有了double，所以没有必要使用Scanner.nextDouble()。nextDouble()方法将输入的下一个标记扫描为双精度。你应该做的是sum += number

Answer 2

这是最新的代码-

import java.io.*;
import java.util.Scanner;

public class theman {
    public static void main(String[] args) throws IOException{

    // Variables
    int counter;
    int userEntries = 5;
    double sum = 0;

    // Creating a new Scanner
    Scanner scanner = new Scanner(System.in);

    // Loop for the five entries
    for (counter = 1; counter <= userEntries; counter++) {
         System.out.print("Please enter a number " + counter + ": ");
         sum += scanner.nextDouble();
    }

    // Print statements
    System.out.println("The average is: " + sum / userEntries);


  } // End of method header
} // End of class header

Answer 3

final int userEntries = 2;
Scanner in = new Scanner(System.in);
double sum = 0.0;

for (int counter = 1; counter <= userEntries; ++counter) {
    System.out.printf("Please enter a number %d: ", counter);
    sum += in.nextDouble();
}

System.out.printf("The average is: %.2f%n", sum / userEntries);