Question

我是Java编程的新手（2周后），目前正在练习数组。

我的代码如下：

import java.util.Scanner;

public class LA2_2_1 {
    public static void main (String[] args)
    {
        Scanner scan = new Scanner(System.in);
        int x;
        double avg;
        double num = 0;

        System.out.print("Enter the number of items: ");
        x = scan.nextInt();

        int [] numbers = new int [x];
        double sum = 0;
        sum = sum + num;    

        for (int index = 0; index < numbers.length; index++)
        {
            System.out.print("Enter the numbers: ");
            num = scan.nextDouble();
            sum = sum + num;
            System.out.println(sum);
        }
        avg = sum/x;
        System.out.println("The average is " + avg);        
    }
}

输出：

Enter the number of items: 10

Enter the numbers: 3.4 5 6 1 6.5 7.8 3.5 8.5 6.3 9.5

3.4

Enter the numbers: 8.4

Enter the numbers: 14.4

Enter the numbers: 15.4

Enter the numbers: 21.9

Enter the numbers: 29.7

Enter the numbers: 33.2

Enter the numbers: 41.7

Enter the numbers: 48.0

Enter the numbers: 57.5

The average is 5.75

我的问题是，如何格式化代码，以便"Enter the numbers"只出现一次？我只是希望程序向用户询问他们想要输入的一系列数字。我不希望它输出多个“输入数字”。

我认为这可能与for循环中的输出有关，但我不是太积极。我尝试将其取出，“输入数字”的平均值和输出均转为0.0。

任何输入都会有所帮助。

谢谢

Answer 1

只需从

更改for循环即可

for (int index = 0; index < numbers.length; index++)
{
    System.out.print("Enter the numbers: ");
    num = scan.nextDouble();
    sum = sum + num;
    System.out.println(sum);
}

到

System.out.print("Enter the numbers: ");
for (int index = 0; index < numbers.length; index++)
{
    num = scan.nextDouble();
    sum = sum + num;
}
System.out.println(sum);

Answer 2

每次for循环运行时，仔细查看代码，都会打印出

行

 System.out.print("Enter the numbers: ");

设置数量的次数，在这种情况下为10。

为了解决此问题，您需要在System.out.print("Enter the numbers: ");循环之前添加for。

Answer 3

它只是简单地将输入提示语句放在for循环外：

System.out.print("Enter the numbers: ");

for (int index = 0; index < numbers.length; index++)
{
        num = scan.nextDouble();
        sum = sum + num;           
}
System.out.println(sum); // sum print statement outside loop to get total sum

Answer 4

只需在循环外移动print语句即可。请尝试此工作链接http://rextester.com/live/ZDRYM2149

class Rextester
{  
    public static void main (String[] args)
    {
        Scanner scan = new Scanner(System.in);
        int x;
        double avg;
        double num = 0;

        System.out.print("Enter the number of items: ");
        x = scan.nextInt();

        int [] numbers = new int [x];
        double sum = 0;
        sum = sum + num;    
        System.out.print("Enter the numbers: ");
        for (int index = 0; index < numbers.length; index++)
        {
            num = scan.nextDouble();
            sum = sum + num;
        }
        System.out.println("The sum is " + sum);
        avg = sum/x;
        System.out.println("The average is " + avg);

    }
}

Answer 5

如果您真的在学习数组，请考虑我的答案，因为在您的代码中您没有使用数组

public static void main(String args[])
    {
        //sb object for getting the actual int
        StringBuilder sb = new StringBuilder("");
        Scanner scan = new Scanner(System.in);  
        int x;
        //this is for the array element of numbers e.g. numbers[y]
        int y=0;

        double sum=0;
        double avg;
        System.out.print("Enter the number of items: ");
        x = scan.nextInt();
        //please add the scan.nextLine that is why you are getting 
        scan.nextLine();
        double[] numbers=new double[x];
        System.out.print("Enter the numbers followed by space:");
        String numberEntered=scan.nextLine();

        for(int i=0;i<numberEntered.length();++i)
        {
            //everytime loop iterate new sb with empty value is created
            sb=new StringBuilder("");
                while(i<numberEntered.length()&&numberEntered.charAt(i)!=' ')
                {
                    //get the actual String integer not containing space
                    sb.append(numberEntered.charAt(i));
                    ++i;
                }
                //convert the String actual integers to integer
            numbers[y]=Double.parseDouble(sb.toString());
            //increment y for the array element of numbers
                ++y;    
        }
        //get the sum using foreach loop containing the array of numbers
        for(double myNumbers:numbers)
        {
            sum+=myNumbers;
        }

        avg=sum/x;
        System.out.println("The average is " + avg);




    }

如何使用Java在for循环中一次输出多个数字

5 个答案: