如何在不使用split和stringtokenizer的情况下在java中反转字符串中的单词
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How to reverse words in string in java without using split and stringtokenizer
提问by Raaaj
I want to reverse words in string of java without using split method and StringTokenizer.
For ex. How are youmust be printed in you are How. I tried but I failed to do it.
Any help will be appreciated.
我想在不使用 split 方法和StringTokenizer. 例如。How are you必须打印在you are How. 我试过了，但我没能做到。任何帮助将不胜感激。
采纳答案by Scientist
Try below code snippet
试试下面的代码片段
import java.util.ArrayList;
public class ReverseString
{
public static void main(String args[])
{
String myName = "Here we go";
ArrayList al = new ArrayList();
al = recursiveReverseMethod(myName,al);
al.trimToSize();
StringBuilder sb = new StringBuilder();
for(int i = al.size()-1; i>=0;i--)
{
sb.append(al.get(i)+" ");
}
System.out.println(sb);
}
public static ArrayList recursiveReverseMethod(String myName,ArrayList al)
{
int index = myName.indexOf(" ");
al.add(myName.substring(0, index));
myName = myName.substring(index+1);
if(myName.indexOf(" ")==-1)
{
al.add(myName.substring(0));
return al;
}
return recursiveReverseMethod(myName,al);
}
}
回答by sathish_at_madison
Here is another flavor based on the old time logic of String reversal in 'C'., from this thread.,
这是基于'C'中字符串反转的旧时间逻辑的另一种风格。，来自这个线程。，
class testers {
public static void main(String[] args) {
String testStr="LongString";
testers u= new testers();
u.reverseStr(testStr);
}
public void reverseStr(String testStr){
char[] d= testStr.toCharArray();
int i;
int length=d.length;
int last_pos;
last_pos=d.length-1;
for (i=0;i<length/2;i++){
char tmp=d[i];
d[i]=d[last_pos-i];
d[last_pos-i]=tmp;
}
System.out.println(d);
}
}
回答by PratLee
I would do this:
我会这样做：
public static String reverseWordsWithoutSplit(String sentence){
if (sentence == null || sentence.isEmpty()) return sentence;
int nextSpaceIndex = 0;
int wordStartIndex = 0;
int length = sentence.length();
StringBuilder reversedSentence = new StringBuilder();
while (nextSpaceIndex > -1){
nextSpaceIndex = sentence.indexOf(' ', wordStartIndex);
if (nextSpaceIndex > -1) reversedSentence.insert(0, sentence.substring(wordStartIndex, nextSpaceIndex)).insert(0, ' ');
else reversedSentence.insert(0, sentence.subSequence(wordStartIndex, length));
wordStartIndex = nextSpaceIndex + 1;
}
return reversedSentence.toString();
}
