LeetCode 557. Reverse Words in a String III

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest"
Output: "s'teL ekat edoCteeL tsetnoc"

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

class Solution {
public:
    string reverseWords(string s) {
           auto it1=s.begin();
           auto it2=it1;
           for(;it2!=s.end()+1;it2++){
               if(*it2==' '||it2==s.end()){
                  reverse(it1,it2);
                  it1=it2+1;
               }    
           }
           return s;
    }
};