将“的每个单词颠倒过来”；“你好，世界”；用Java编写字符串

我想反转Java中字符串的每个单词（不是整个字符串，只是每个单词）

---

示例：如果输入字符串是“Hello World”，那么输出应该是“olleH dlroW”

在

将
拆分为
数组
后，需要对每个单词执行此操作

public String reverse(String word) {
    char[] chs = word.toCharArray();

    int i=0, j=chs.length-1;
    while (i < j) {
        // swap chs[i] and chs[j]
        char t = chs[i];
        chs[i] = chs[j];
        chs[j] = t;
       i++; j--;
    }
    return String.valueOf(chs);
}

公共字符串反转（字符串字）{
char[]chs=word.toCharArray（）；
int i=0，j=chs.length-1；
而（i
这里有一个接受字符串并将其反转的方法

public String reverse ( String s ) {
            int length = s.length(), last = length - 1;
            char[] chars = s.toCharArray();
            for ( int i = 0; i < length/2; i++ ) {
                char c = chars[i];
                chars[i] = chars[last - i];
                chars[last - i] = c;
            }
            return new String(chars);
        }

这应该能奏效。这将遍历源字符串中的每个单词，使用的内置
reverse（）
方法将其反转，然后输出反转的单词

String source = "Hello World";

for (String part : source.split(" ")) {
    System.out.print(new StringBuilder(part).reverse().toString());
    System.out.print(" ");
}

输出：

olleH dlroW 

    This is my sentence        
    sihT si ym ecnetnes        

olleH dlroW

注释：评论者正确地指出了我认为应该在这里提及的一些事情。本例将在结果的末尾追加一个额外的空格。它还假设您的单词之间有一个空格，并且您的句子中没有标点符号。
这里有一个最简单的解决方案，它甚至不使用任何循环

public static void main(String[] args) {
        System.out.println(eatWord(new StringBuilder("Hello World This Is Tony's Code"), new StringBuilder(), new StringBuilder()));
    }
static StringBuilder eatWord(StringBuilder feed, StringBuilder swallowed, StringBuilder digested) {
    for (int i = 0, size = feed.length(); i <= size; i++) {
        if (feed.indexOf(" ") == 0 || feed.length() == 0) {
            digested.append(swallowed + " ");
            swallowed = new StringBuilder();
        } else {
            swallowed.insert(0, feed.charAt(0));
        }
        feed = (feed.length() > 0)  ? feed.delete(0, 1) : feed ;
    }
    return digested;
}

public class olleHdlroW {
    static String reverse(String in, String out) {
        return (in.isEmpty()) ? out :
            (in.charAt(0) == ' ')
            ? out + ' ' + reverse(in.substring(1), "")
            : reverse(in.substring(1), in.charAt(0) + out);
    }
    public static void main(String args[]) {
        System.out.println(reverse("Hello World", ""));
    }
}

即使这是家庭作业，也可以随意复制并提交。你要么会得到一个额外的学分（如果你能解释它是如何工作的），要么会因为剽窃而被抓住（如果你不能）。
了解你的图书馆；-）

考虑到分隔符可以是多个空格/选项卡，并且我们希望保留它们：

public static String reverse(String string)
{
    StringBuilder sb = new StringBuilder(string.length());
    StringBuilder wsb = new StringBuilder(string.length());
    for (int i = 0; i < string.length(); i++)
    {
        char c = string.charAt(i);
        if (c == '\t' || c == ' ')
        {
            if (wsb.length() > 0)
            {
                sb.append(wsb.reverse().toString());
                wsb = new StringBuilder(string.length() - sb.length());
            }
            sb.append(c);
        }
        else
        {
            wsb.append(c);
        }
    }
    if (wsb.length() > 0)
    {
        sb.append(wsb.reverse().toString());
    }
    return sb.toString();

}

公共静态字符串反转（字符串）
{
StringBuilder sb=新的StringBuilder（string.length（））；
StringBuilder wsb=新的StringBuilder（string.length（））；
对于（int i=0；i0）
{
sb.append（wsb.reverse（）.toString（））；
wsb=新的StringBuilder（string.length（）-sb.length（））；
}
sb.附加（c）；
}
其他的
{
追加（c）；
}
}
如果（wsb.length（）>0）
{
sb.append（wsb.reverse（）.toString（））；
}
使某人返回字符串（）；
}
我假设您可以直接打印结果（您刚才说“输出应该是…”）；-）

或返回反向字符串：

String str = "Hello World";
StringBuilder reversed = new StringBuilder();
for (String word : str.split(" ")) {
  reversed.append(reverse(word));
  reversed.append(' ');
}
System.out.println(reversed);

String reverse(String s) {
  StringBuilder b = new StringBuilder();
  for (int idx = s.length() - 1; idx >= 0; idx--)
      b.append(s.charAt(idx));
  return b.toString();
}

我是一个C/C++的人，在面试中练习java让我知道一些东西是否可以改变或改进。下面允许使用多个空格和换行符

第一个是使用StringBuilder

public static String reverse(String str_words){
    StringBuilder sb_result = new StringBuilder(str_words.length());
    StringBuilder sb_tmp = new StringBuilder();
    char c_tmp;
    for(int i = 0; i < str_words.length(); i++){
        c_tmp = str_words.charAt(i);    
        if(c_tmp == ' ' || c_tmp == '\n'){
            if(sb_tmp.length() != 0){   
                sb_tmp.reverse();
                sb_result.append(sb_tmp);
                sb_tmp.setLength(0);
            }   
            sb_result.append(c_tmp);
        }else{
            sb_tmp.append(c_tmp);
        }
    } 
    if(sb_tmp.length() != 0){
        sb_tmp.reverse();
        sb_result.append(sb_tmp);
    }
    return sb_result.toString();
}

公共静态字符串反转（字符串str\u字）{
StringBuilder sb_结果=新的StringBuilder（str_words.length（））；
StringBuilder sb_tmp=新StringBuilder（）；
char c_tmp；
for（int i=0；i

这个正在使用char[]。我认为它更有效

public static String reverse(String str_words){
    char[] c_array = str_words.toCharArray();
    int pos_start = 0;
    int pos_end;
    char c, c_tmp; 
    int i, j, rev_length;
    for(i = 0; i < c_array.length; i++){
        c = c_array[i];
        if( c == ' ' || c == '\n'){
            if(pos_start != i){ 
                pos_end = i-1;
                rev_length = (i-pos_start)/2;
                for(j = 0; j < rev_length; j++){
                    c_tmp = c_array[pos_start+j];
                    c_array[pos_start+j] = c_array[pos_end-j];
                    c_array[pos_end-j] = c_tmp;
                }
            }
            pos_start = i+1;
        }
    }
    //redundant, if only java had '\0' @ end of string
    if(pos_start != i){
        pos_end = i-1;
        rev_length = (i-pos_start)/2;
        for(j = 0; j < rev_length; j++){
            c_tmp = c_array[pos_start+j];
            c_array[pos_start+j] = c_array[pos_end-j];
            c_array[pos_end-j] = c_tmp;
        }
    }   
    return new String(c_array);
}

公共静态字符串反转（字符串str\u字）{
char[]c_数组=str_words.toCharArray（）；
int pos_start=0；
int pos_end；
字符c，c_tmp；
int i，j，rev_长度；
对于（i=0；i
使用split（），您只需更改希望拆分的内容即可

public static String reverseString(String str)
{
    String[] rstr;
    String result = "";
    int count = 0;
    rstr = str.split(" ");
    String words[] = new String[rstr.length];
    for(int i = rstr.length-1; i >= 0; i--)
    {
        words[count] = rstr[i];
        count++;
    }

    for(int j = 0; j <= words.length-1; j++)
    {
        result += words[j] + " ";
    }

    return result;


}

publicstaticstringreversestring（stringstr）
{
字符串[]rstr；
字符串结果=”；
整数计数=0；
rstr=str.split（“”）；
字符串字[]=新字符串[rstr.length]；
对于（int i=rstr.length-1；i>=0；i--）
{
字[count]=rstr[i]；
计数++；
}
对于（int j=0；j我在处理这个问题时得出了这个答案。我试图不使用嵌套for循环解决方案O（N^2）。我强迫自己使用堆栈来取乐：D

    public StringBuilder reverseWord(String input) {
        char separator = ' ';
        char[] chars = input.toCharArray();
        Stack<Character> stack = new Stack<Character>();
        StringBuilder sb = new StringBuilder(chars.length);


        for(int i = 0; i < chars.length; i++) {

            if(chars[i] != separator) { //letters
                stack.push(chars[i]);

                //if not last letter don't go any further
                if(i != chars.length - 1) { continue; }

            }

            while(!stack.isEmpty()) {
                sb.append(stack.pop());
            }
            sb.append(separator);

        }
        //remove the last separator
        sb.deleteCharAt(sb.length() - 1);
        return sb;
    }

publicstringbuilderreverseeword（字符串输入）{
字符分隔符=“”；
char[]chars=input.toCharArray（）；
堆栈=新堆栈（）；
StringBuilder sb=新StringBuilder（字符长度）；
for（int i=0；i
String input=“Hello World！”；
字符串temp=“”；
字符串结果=”；
用于（int i）
public static String reverseString(String str)
{
    String[] rstr;
    String result = "";
    int count = 0;
    rstr = str.split(" ");
    String words[] = new String[rstr.length];
    for(int i = rstr.length-1; i >= 0; i--)
    {
        words[count] = rstr[i];
        count++;
    }

    for(int j = 0; j <= words.length-1; j++)
    {
        result += words[j] + " ";
    }

    return result;


}

    public StringBuilder reverseWord(String input) {
        char separator = ' ';
        char[] chars = input.toCharArray();
        Stack<Character> stack = new Stack<Character>();
        StringBuilder sb = new StringBuilder(chars.length);


        for(int i = 0; i < chars.length; i++) {

            if(chars[i] != separator) { //letters
                stack.push(chars[i]);

                //if not last letter don't go any further
                if(i != chars.length - 1) { continue; }

            }

            while(!stack.isEmpty()) {
                sb.append(stack.pop());
            }
            sb.append(separator);

        }
        //remove the last separator
        sb.deleteCharAt(sb.length() - 1);
        return sb;
    }

String someString = new String("Love thy neighbor");
    System.out.println(someString);
    char[] someChar = someString.toCharArray();
    int j = someChar.length - 1;
    char temp;
    for (int i = 0; i <= someChar.length / 2; i++) {
        temp = someChar[i];
        someChar[i] = someChar[j];
        someChar[j] = temp;
        j--;
    }
    someString = new String(someChar);
    System.out.println(someString);

Love thy neighbor
robhgien yht evoL

    String input = "Hello World!";

    String temp = "";
    String result = "";

    for (int i = 0; i <= input.length(); i++) {
        if (i != input.length() && input.charAt(i) != ' ') {
            temp = input.charAt(i) + temp;
        } else {
            result = temp + " " + result;
            temp = "";
        }
    }

    System.out.println("the result is: " + result);

public static String reversePhrases(String s)
{
    char[] buf = s.toCharArray();
    int len = buf.length;
    int start = 0;
    for (int i = 0; i < len; i++) {
        if (buf[i] == ' ' || i == (len-1)) {
            if (i == (len-1)) {
                i = len;
            }
            int end = (start + i)/2;
            for (int j = start; j < end; j++) {
                char c = buf[j];
                int pos = (start + i) - j - 1;
                buf[j] = buf[pos];
                buf[pos] = c;
            }
            start = i + 1;    
        }
    }
    return new String(buf);
}

String reverseString(String string)
{
    String newString = "";
    for(int x = string.length() - 1; x > -1; x ++)
        newString += string.charAt(x);
    return newString;
}

class ReverseWordsInString{
    public static String reverse(String s1){
            int l = s1.length();
            if (l>1)
                    return(s1.substring(l-1) + reverse(s1.substring(0,l-1)));
            else
                    return(s1.substring(0));
    }
    public static void main(String[] args){
            String st = "Hello My World!";
            String r = "";
            for (String word : st.split(" "))
                    r += " "+ reverse(word);
            System.out.println("Reversed words in the given string: "+r.trim());
    }
}

String helloWorld = "He\u0308llo World"; // Hëllo World
StringBuilder reverseStringBuilder = new StringBuilder(helloWorld.length());
BreakIterator wordBreakIterator = BreakIterator.getWordInstance();
wordBreakIterator.setText(helloWorld);

int wordStart = wordIterator.first();
int wordEnd = wordIterator.next();

while (wordEnd != BreakIterator.DONE) {
    String word = helloWorld.substring(wordStart,wordEnd);
    if (Character.isLetterOrDigit(word.charAt(0))) {
        // "Hello" or "World" in our example
        BreakIterator characterBreakIterator = BreakIterator.getCharacterInstance();
        characterBreakIterator.setText(word);
        int characterEnd = characterBreakIterator.last();
        int characterStart = characterBreakIterator.previous();
        while (characterStart != BreakIterator.DONE) {
            reverseStringBuilder.append(word.substring(characterStart, characterEnd));

            characterEnd = characterStart;
            characterStart = characterBreakIterator.previous();
        }
    } else {
        // " " in our example
        reverseStringBuilder.append(word);
    }
    wordStart = wordEnd;
    wordEnd = wordIterator.next();
}

String dlroWolleh = reverseStringBuilder.toString(); // "dlroW ollëH"

 package MujeebWorkspace.helps;
 // javamujeeb@gmail.com

 public class Mujeeb {

     static String str= "This code is simple to reverse the word without changing positions";
     static String[] reverse = str.split(" ");

     public static void main(String [] args){  
         reverseMethod();
     }

     public static void reverseMethod(){
         for (int k=0; k<=reverse.length-1; k++) {
             String word =reverse[reverse.length-(reverse.length-k)];
             String subword = (word+" ");
             String [] splitsubword = subword.split("");

             for (int i=subword.length(); i>0; i--){
                 System.out.print(splitsubword[i]);  
             }
         }
     }
 }

for(int i = 0; i < input.length(); i++){
    output = output + input.substring((input.length()-i)-1, input.length()-i);
}

    public String reverseSentence(String input)
      {
        String[] words = input.split(" ");
        StringBuilder builder = new StringBuilder();
        for (String s : words)
        {
            String rev = " ";
            for (int i = 0; i < s.length(); i++)
            {
                rev = s.charAt(i) + rev;
            }

            builder.append(rev);
        }

        return builder.toString().trim();
      }

    This is my sentence        
    sihT si ym ecnetnes        

public String rev(String rest) {
    if (rest.equals(""))
        return "";
    return rev(rest.substring(1)) + rest.substring(0,1);
}

public String reverse(String arg) {
    char[] s = arg.toCharArray();
    StringBuilder sb = new StringBuilder();
    boolean reverse = false;
    boolean isChar = false;
    int insertPos = 0;

    for (int i = 0; i < s.length; i++) {
        isChar = Character.isAlphabetic(s[i]);
        if (!reverse && isChar) {
            sb.append(s[i]);
            insertPos = i;
            reverse = true;
        } else if (reverse && isChar) {
            sb.insert(insertPos, s[i]);
        } else if (!reverse && !isChar) {
            sb.append(s[i]);
        } else if (reverse && !isChar) {
            reverse = false;
            sb.append(s[i]);
        }
    }

    return sb.toString();
}

with and without api.

public class Reversal {
    public static void main(String s[]){
        String str= "hello world";
        reversal(str);
    }

    static void reversal(String str){
        String s[]=str.split(" ");
        StringBuilder noapi=new StringBuilder();
        StringBuilder api=new StringBuilder();
        for(String r:s){
            noapi.append(reversenoapi(r));
            api.append(reverseapi(r));
        }
        System.out.println(noapi.toString());
        System.out.println(api.toString());
    }

    static String reverseapi(String str){
        StringBuilder sb=new StringBuilder();
        sb.append(new StringBuilder(str).reverse().toString());
        sb.append(' ');
        return sb.toString();

    }

    static String reversenoapi(String str){
        StringBuilder sb=new StringBuilder();
        for(int i=str.length()-1;i>=0;i--){
            sb.append(str.charAt(i));
        }
        sb.append(" ");
        return sb.toString();
    }
}

public static void main(String args[]) {
    String s, rev = "";
    Scanner in = new Scanner(System.in);

    System.out.println("Enter a string to reverse");
    s = in.nextLine();

    int length = s.length();
    // char[] cs=s.toCharArray();
    int l, r;
    int i = 0;
    while (i < length) {
        l = i; // starting index
        // find length of sub-block to reverse copy
        while (i < length && s.charAt(i) != ' ') { 
            i++;
        }
        r = i - 1; // ending index
        for (int j = r; j >= l; j--) { // copy reverse of sub-block
            rev = rev + s.charAt(j);
        }
        rev = rev + " "; // add the whitespace
        i++;
    }

    System.out.println("Reverse of entered string is: " + rev);
}

import java.io.IOException;
import java.util.ArrayList;

public class WordReverse {

    public static void main(String[] args) throws IOException {

        String inputStr = "Hello World";
        String reversed = "";
        ArrayList<String> alist = new ArrayList<String>();

        for (int i = inputStr.length() - 1; i >= 0; i--) {
            if (inputStr.charAt(i) != ' ') {
                reversed = reversed + inputStr.charAt(i);
            } else {
                alist.add(reversed);
                reversed = "";
            }
        }
        alist.add(reversed);
        String result = "";

        for (int i = alist.size() - 1; i >= 0; i--) {
            result = result + alist.get(i);
            result = result + " ";
        }
        System.out.println(result);
    }
}

public String reverseString(String str){
    String str = "Hello Wrold";
    int start = 0;

    for (int i = 0; i < str.length(); i++) {

        if (str.charAt(i) == ' ' || i == str.length() - 1) {

            int end = 0;

            if (i == str.length() - 1) {
                end = i;
            } else {
                end = i - 1;
            }

            str = swap(str, start, end);
            start = i + 1;
        }
    }
    System.out.println(str);
   }

 private static String swap(String str, int start, int end) {

    StringBuilder sb = new StringBuilder(str);

    while (start < end) {
        sb.setCharAt(start, str.charAt(end));
        sb.setCharAt(end, str.charAt(start));
        start++;
        end--;
    }
    return sb.toString();
}

    public static String reverseAllWords(String str) {
    String[] arr = str.split(" ");
    String res = "";
    for (int x = 0; x < arr.length; x++) {
        res = res + Stream.of(arr[x].split("")).reduce("", (a, b) -> b + a) + " ";
    }
    return res;
}

olleH dlroW