在Java中如何输出缩进字符串？

huangapple
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英文:

How to output indenting strings in Java?

问题

我正在做汉诺塔问题，我想输出所有移动步骤（2^n-1），并且逐步增加前导空格。

例如：

  1.     从顶部移动盘子从...
  2.         从顶部移动盘子从...
  3.             从顶部移动盘子从...
  4.                 从顶部移动盘子从...

...以此类推。

我尝试创建一个单独的“space”方法，但不确定如何将其实现到程序中。

这是我目前代码的一部分：

  1. public static void towersOfHanoi(int disk, int source, int dest){
  2.     int temp;
  3.     if (disk == 1) {
  4.         moveDisk(source,dest);
  5.     }
  6.     else {
  7.         temp = 6 - source - dest;
  8.         towersOfHanoi(disk-1,source,temp);
  9.         moveDisk(source,dest);
  10.         towersOfHanoi(disk-1,temp,dest);
  11.     }
  12. }
  14. private static void moveDisk(int source, int dest) {
  15.     System.out.println("从 " + source + " 移动顶部盘子到 " + dest);
  16. }
英文:

I am doing the Towers of Hanoi and I want to output all the moves (2^n-1) with increasing leading spaces.
E.g.

  1. Moving top disk from....
  2.     Moving top disk from....
  3.         Moving top disk from....
  4.             Moving top disk from....

... and so on.

I tried to create a separate "space" method, but I'm unsure as to how to implement it into the program

This is a part of my code right now.

  1. public static void towersOfHanoi(int disk, int source, int dest){
  2. 		int temp;
  3. 		if (disk == 1) {
  4. 			moveDisk(source,dest);
  5. 		}
  6. 		else {
  7. 			temp = 6 - source - dest;
  8. 			towersOfHanoi(disk-1,source,temp);
  9. 			moveDisk(source,dest);
  10. 			towersOfHanoi(disk-1,temp,dest);
  11. 		}
  12. 	}
  13. 	
  14. 	private static void moveDisk(int source, int dest) {
  15. 		System.out.println("Moving top disk from " + source + " to " + dest);
  16. 	}

答案1

得分: 0

你可以通过Apache Commons Framework.来import org.apache.commons.lang3.StringUtils。

然后使用：

  1. StringUtils.leftPad("123456", tab_length * 2)
  2. //或者以你希望格式化左侧空间的方式

这是最方便的方法，否则你可以编写一个自定义的leftPad方法，使用StringBuilder或类似的方法。

英文:

You can import org.apache.commons.lang3.StringUtils via the Apache Commons Framework.

Then use:

  1. StringUtils.leftPad("123456", tab_length * 2) 
  2. //or however you want to format the left space

This is the most convenient way, otherwise, you can write a custom leftPad method using StringBuilder or something similar.

答案2

得分: 0

我已使用字符串构建器来实现缩进。缩进的数量由类“indents”的静态变量定义，并且每次调用moveDisk方法时都使用for循环。

  1. public class Test {
  3.     static Integer indents = -2;
  4.     static String indent = "   ";
  5.     public static void towersOfHanoi(int disk, int source, int dest){
  6.         int temp;
  7.         if (disk == 1) {
  8.             moveDisk(source,dest);
  9.         }
  10.         else {
  11.             temp = 6 - source - dest;
  12.             towersOfHanoi(disk-1,source,temp);
  13.             moveDisk(source,dest);
  14.             towersOfHanoi(disk-1,temp,dest);
  15.         }
  16.     }
  18.     private static void moveDisk(int source, int dest) {
  20.         indents = indents + 1;
  22.         StringBuilder sb = new StringBuilder();
  24.         for(int i = 0; i<=indents; i++){
  25.             sb.append(indent);
  26.         }
  27.         sb.append("Moving top disk from ");
  28.         sb.append(source);
  29.         sb.append( " to ");
  30.         sb.append( dest);
  32.         System.out.println(sb.toString());
  33.     }
  35.     public static void main(String[] args) {
  37.         moveDisk(10, 10);
  38.         moveDisk(1, 10);
  39.         moveDisk(20, 10);
  41.     }
  42. }

结果：

  1. Moving top disk from 10 to 10
  2.    Moving top disk from 1 to 10
  3.       Moving top disk from 20 to 10
英文:

I have used a string builder to implement the indents. The number of indents are defined by a static variable for the class "indents" and a for loop is used each time the moveDisk method is called.

  1. public class Test {
  3.     static Integer indents = -2;
  4.     static String indent = &quot;   &quot;;
  5.     public static void towersOfHanoi(int disk, int source, int dest){
  6.         int temp;
  7.         if (disk == 1) {
  8.             moveDisk(source,dest);
  9.         }
  10.         else {
  11.             temp = 6 - source - dest;
  12.             towersOfHanoi(disk-1,source,temp);
  13.             moveDisk(source,dest);
  14.             towersOfHanoi(disk-1,temp,dest);
  15.         }
  16.     }
  18.     private static void moveDisk(int source, int dest) {
  20.         indents = indents + 1;
  22.         StringBuilder sb = new StringBuilder();
  24.         for(int i = 0; i&lt;=indents; i++){
  25.             sb.append(indent);
  26.         }
  27.         sb.append(&quot;Moving top disk from &quot;);
  28.         sb.append(source);
  29.         sb.append( &quot; to &quot;);
  30.         sb.append( dest);
  32.         System.out.println(sb.toString());
  33.     }
  35.     public static void main(String[] args) {
  37.         moveDisk(10, 10);
  38.         moveDisk(1, 10);
  39.         moveDisk(20, 10);
  41.     }
  42. }

The outcome:

  1. Moving top disk from 10 to 10
  2.    Moving top disk from 1 to 10
  3.       Moving top disk from 20 to 10

huangapple
  • 本文由 发表于 2020年8月13日 13:50:17
  • 转载请务必保留本文链接：https://go.coder-hub.com/63388895.html
  • indentation
  • java
  • output
  • spaces
  • towers-of-hanoi
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