如何使用Java在for循環中一次輸出多個數字

Question

我對Java編程（2周）非常陌生，目前正在練習數組。

我的代碼如下：

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);   
    } 
} 

輸出：

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 

我的問題是，我怎麼能格式化代碼，使我得到"Enter the numbers"只出現一次？我只想讓程序向用戶詢問他們想要輸入的一系列數字。我不希望它輸出多個「輸入數字」。

我認爲這可能與輸出在for循環內有關，但我不太積極。我試着把它拿出來，「輸入數字」的平均值和輸出都變成了0.0。

任何輸入都會有幫助。

謝謝

Answer 1

剛剛從

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

更改for環路

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

每次你for循環運行時，它會打印出的線時間嘛尋找你的代碼

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

對於多次設置數字量，在這種情況下，10

爲了解決這個問題，你會希望for循環之前添加System.out.print("Enter the numbers: ");。

Answer 3

它的簡單只是把輸入提示語句外的for循環：

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

只需動環外的作品打印語句。請試試這個工作環節以及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

考慮我的回答如果你真學問的數組，因爲在你的代碼，你沒有使用你的陣列

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); 




    }