按字母顺序排列字符串(不使用 compareTo 方法) [英] Alphabetize strings (without using compareTo Method)

问题描述

我试图在不使用 compareTo() 的情况下对字符串数组进行排序，但我卡在了 while 循环中.有没有办法在不使用 compareTo() 或 Arrays.sort() 的情况下按字母顺序对字符串进行排序?

I'm trying to sort an array of strings without using compareTo(), but I am getting stuck on my while loop. Is there a way to alphabetically sort strings without using compareTo() or Arrays.sort()?

public class mycode 
{

    public static void main(String[ ] args)
    {
            String[ ] ar = {"hello", "java", "elephant", "array"};
            mycode.display(ar);
            mycode.bubbleSort(ar);
            mycode.display(ar);
    }
    static void display(String[] ar)
    {
        System.out.println("***********************");
        for(int i = 0; i < ar.length; i++)
        {
            System.out.println(ar[i]);
        }
        System.out.println("***********************");

    }
    static void bubbleSort(String[] ar)
    {
        int theFollower;
        for(int currStart = 1; currStart < ar.length; currStart++)
        {
            theFollower = currStart;
            while(theFollower != 0 && ar[theFollower] < ar[theFollower - 1]) //this is where my problem is
            {
                String swap = ar[theFollower];
                ar[theFollower] = ar[theFollower - 1];
                ar[theFollower - 1] = swap;
                theFollower--;
            }
        }
    }

}

按字母顺序排列是我的目标，所以我的输出如下

Alphabetization is my goal, so my output would be the following

***********************
hello
java
elephant
array
***********************
***********************
array
elephant
hello
java
***********************

我使用建议的想法添加了这个方法，但我不确定我会放置什么来遍历字符串的索引

I added this method using the idea that was suggested, but I am unsure what I would put in place to run through the index of the string

    int alphabetize(String a, String b)
    {
    String A = a.toLowerCase();
    String B = b.toLowerCase();
    if (A < B)
    {
        return -1;
    }
    else if (A > B)
    {
        return  1;
    }
    else
    {
    }
    }

推荐答案

我假设这是家庭作业，因为显而易见的方法就是使用 compareTo()，所以我会给你关于如何编写自己的方法进行比较的提示.你想要带签名的东西

I'm assuming this is homework, since the obvious way is just to use compareTo(), so I'll give you a hint on how to write your own method to do the comparison. You want something with signature

int compareStrings(String s, String t);

返回 -1 或 0 或 1 取决于 s 是按字母顺序排列在前面、等于或在字母表中 t 之后.

that returns -1 or 0 or 1 depending on whether s is alphabetically before, equal to or after t in the alphabet.

逐个字符遍历两个String，并且在每个阶段，如果s中的字符小于t(这里你可以使用<)然后返回-1；如果更大，则返回1；如果它们相等，请继续.

Go through the two Strings character by character, and at each stage, if the character from s is less than that of t (here you can use <) then return -1; if it's greater, then return 1; if they're equal, keep going.

如果 s 中的字符用完了，但 t 中还有一些字符，则返回 -1，如果是其他方式回合然后返回1.如果同时用完，返回0.

If you run out of characters in s but still have some in t, then return -1, and if it's the other way round then return 1. If you run out of both at the same time, return 0.

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