java - 如何根据用户输入打印多个整数数组？

Question

我正在创建一个java程序，它提示用户输入数组中的项目数(非负整数)，读取它，并将其保存在int变量中。然后它提示用户输入所有项目的值并将它们保存在 int 数组中。然后，程序以 [x1, x2, ... ,xn] 的形式打印数组的内容。无需用户验证。该程序本来应该运行良好，但是，当我尝试为用户输入多个输入时，输出出现问题。

而不是显示这个:

Enter the number of items: 2
Enter the value of all items (separated by space): 88
Enter the value of all items (separated by space): 99
The values are: [88, 99]

输出变成这样:

Enter the number of items: 2
Enter the value of all items (separated by space) : 88
Enter the value of all items (separated by space) : 99
The values are: [88]
The values are: [99]

此外，当我输入 0 作为项目数时，输出应该显示此

Enter the number of items: 0
The values are: []

但我的输出显示了这一点:

Enter the number of items: 0

当项目数为0时，它甚至不显示值的括号。下面附上我的编码:

import java.util.Scanner;


public class PrintArray{



public static void main(String[] args) {
 // Declare variables
      int numItems;
      int[] items;  // Declare array name, to be allocated after numItems is known


  // Prompt for a non-negative integer for the number of items;
  // and read the input as "int". No input validation.
  Scanner in = new Scanner(System.in);
  System.out.print("Enter the number of items: ");
  numItems = in.nextInt();


  // Allocate the array
  items = new int[numItems];

  // Prompt and read the items into the "int" array, if array length > 0
  if (items.length > 0) {

     for (int i = 0; i < items.length; ++i) {
        System.out.print("Enter the value of all items (separated by space) : ");
        items[i] = in.nextInt();

     }
  }

  // Print array contents, need to handle first item and subsequent items differently

  for (int i = 0; i < items.length; ++i) {
     if (i == 0) {
        // Print the first item without a leading commas
        System.out.println("The values are: [" + items[i] + "]");
     } else {
        // Print the subsequent items with a leading commas
        System.out.println("The values are: [" + items[i] + "]");
     }

  }



  }
}

如果有人能帮助我，那就太好了。非常感谢!

Answer 1

在循环中，您将打印整个句子，而您可以将数组元素附加到字符串中，以便稍后打印。第二个问题是因为数组为空，这使得第一次迭代本身的循环条件为假。因此循环体不会被执行。

您可以尝试如下所示的操作。

String output = "[";
for (int i = 0; i < items.length; ++i) {
    output += items[i] + ", ";
}

// remove last comma and space
output = output.substring(0, output.length() - 2);
output += "]";
System.out.println("The values are: " + output);