java根据第一个单词的长度反转字符串

Question

我不熟悉Java字符串。 事实上，我有反转单词的代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Test2 {

    public static void main(String[] args) throws IOException
    {
        System.out.println("enter a sentence");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String rev =br.readLine();

        String [] bread = rev.split(" ");
        for(int z =bread.length-1;z>=0;z--)
        {
            System.out.println(bread[z]);
        }

    }
}

对于上述代码，我得到：

Input :Bangalore is a city
Output: City is a Bangalore

但我希望输出如下所示：

Input: Bangalore is a city
Output:cityaisba ng a lore

另一个例子：

Input: Hello Iam New To Java.Java is object Oriented language.
Output: langu age Ori en tedo bjec ti sjava. javaToNe wIamolleH

请帮帮我

Answer 1

我没有像GHajba那样检查代码的有效性。但是，如果希望空间保留在特定位置，可以选择删除所有空间，并根据原始字符串中的索引将其放回原处

全部删除

newBread = newBread.replace(" ", "");

把它们放回去

StringBuilder str = new StringBuilder(newBread);

for (int index = oldBread.indexOf(" ") ;
     index >= 0 ;
     index = oldBread.indexOf(" ", index + 1)) 
{
    str.insert(index, ' ');
}

newBread=str.toString（）

我很快就想到了这个方法，也许没有StringBuilder，可能会有更好的方法，但在找到更好的方法之前，这可能会对您有所帮助

Answer 2

将不带空格的反向单词追加到StringBuffer中

    StringBuffer b = new StringBuffer();
    for (int i = bread.length-1; i >= 0 ; i--) {
        b.append(bread[i]);
    }

然后将原始String的空格插入StringBuffer

    int spaceIndex, prevIndex = 0;        
    while ((spaceIndex = rev.indexOf(" ", prevIndex + 1)) != -1) {
        b.insert(spaceIndex, ' ');
        prevIndex = spaceIndex;
    }

Answer 3

以下是一种方法：

    String rev = br.readLine();

    String [] bread = rev.split(" ");
    int revCounter = 0;
    for(int z = bread.length - 1; z >= 0; z--)
    {
        String word = bread[z];
        for(int i = 0; i < word.length(); i++)
        {
            // If char at current position in 'rev' was a space then
            // just print space. Otherwise, print char from current word.
            if(rev.charAt(revCounter) == ' ')
            {
                System.out.print(' ');
                i--;
            }
            else
                System.out.print(word.charAt(i));

            revCounter++;
        }
    }

Answer 4

当我运行您的代码时，我得到以下结果：

city
a
is
Bangalore

所以，要将它放在一行中，为什么不添加一个空格并打印一行呢

System.out.println("enter a sentence");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String rev = br.readLine();

String[] bread = rev.split(" ");
for (int z = bread.length - 1; z >= 0; z--) {
    System.out.print(bread[z] + " ");
}

Answer 5

试试这个（我使用了一个字符串作为输入）：

    String original = "Bangalore is a city";
    System.out.println("Original : "+original);

    StringBuilder inverted = new StringBuilder();
    StringBuilder output = new StringBuilder();
    String temp = "";

    String[] split = original.split("\\s+");

    for (int i = split.length - 1; i >= 0; i--) {
        inverted.append(split[i]);
    }

    temp = inverted.toString();

    for (String string : split) {
        int currLenght = string.length();
        String substring = temp.substring(0,currLenght);
        temp = temp.replaceAll(substring, "");
        output.append(substring).append(" ");
    }

    System.out.println("Converted : "+output.toString());