使用string.compareTo（）插入排序 [英] Insertion Sort using string.compareTo()

问题描述

据我所知，我在这里实现了基本的插入排序。输出是相同的数组，未排序。我正确使用compareTo吗？我不确定这是一个大于或小于零的数字意味着什么。

As far as I can tell, I have implemented the basic insertion sort here. The output is the same array, unsorted. Am I making use of compareTo correctly? I am unsure what it means by being some number greater than or less than zero.

import java.util.Arrays;

public class Test {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    int lineNumber = 5;
    int i,j;
    String key;
    String[] inputArray = {"E","D","C","B","A","B"};
    System.out.println(Arrays.toString(inputArray));
    for (j = 1; j < lineNumber; j++) {
        key = inputArray[j];
        i = j - 1;
        while (i >= 0) {
            if (key.compareTo(inputArray[i]) < 0) {
                break;
            }
            inputArray[i + 1] = inputArray[i];
            i--;
        }
        inputArray[i + 1] = key;
        System.out.println(Arrays.toString(inputArray));
    }
    System.out.println(Arrays.toString(inputArray));
}

运行：

[E, D, C, B, A, B]

[E, D, C, B, A, B]

[E, D, C, B, A, B]

[E, D, C, B, A, B]

[E, D, C, B, A, B]

[E, D, C, B, A, B]

BUILD SUCCESSFUL (total time: 0 seconds)

推荐答案

正如所指出：不，你没有正确使用的compareTo（）。下面的代码按预期工作。

As pointed out: no, you are not making correct use of compareTo(). The below code works as intended.

public static void main(String[] args) {
  int i,j;
  String key;
  String[] inputArray = {"E","D","C","B","A","B"};
  System.out.println(Arrays.toString(inputArray));
  for (j = 1; j < inputArray.length; j++) { //the condition has changed
    key = inputArray[j];
    i = j - 1;
    while (i >= 0) {
      if (key.compareTo(inputArray[i]) > 0) {//here too
        break;
      }
      inputArray[i + 1] = inputArray[i];
      i--;
    }
    inputArray[i + 1] = key;
    System.out.println(Arrays.toString(inputArray));
  }
  System.out.println(Arrays.toString(inputArray));
}

为什么 compareTo（）在其他答案中，它所做的事情得到了很好的解释。除此之外，我改变了直到应该运行for循环的值，它应该运行到数组的末尾（array.length），而不是直到任何其他数字。

Why the compareTo() does what it does is explained very well in the other answers. Besides that i changed until what value the for-loop should run, it should run until the end of the array (array.length), not until any other number.

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