Reverse words in a string

Given an input string, reverse the string word by word.

For example,
Given S ="the sky is blue",
Return"blue is sky the".

Click to show clarification.

Clarification:

 

• What constitutes a word?
  A sequence of non-space characters constitutes a word.
• Cocould the input string contain leading or trailing spaces?
  Yes. However, your reversed string shocould not contain leading or trailing spaces.
• How about multiple spaces between two words?
  Reduce them to a single space in the reversed string.

Train of Thought: scan the string from the beginning to the end, not from the space. Put the word into temp until there is a space. Put the word into result as follows. Then, put the word in front of the previous word and add a space. In this way, words and words can be reversed.

class Solution {public:    void reverseWords(string &s) {        int nLen=s.size();        if(nLen<=0)            return;        string temp,result;        int index=0;        while(s[index]==‘ ‘)            index++;        for(int i=index;i<nLen;)        {            if(s[i]!=‘ ‘)            {                temp+=s[i];                i++;            }            else            {                while(s[i]==‘ ‘)                    i++;                if(i==nLen)                    break;                result=" "+temp+result;                temp="";            }        }        s=temp+result;    }};