Reverse Words in a String详解编程语言

Given an input string, reverse the string word by word. 
 
For example, 
Given s = "the sky is blue", 
return "blue is sky the". 
 
Example 
Clarification 
 
- What constitutes a word? 
A sequence of non-space characters constitutes a word. 
 
- Could the input string contain leading or trailing spaces? 
Yes. However, your reversed string should not contain leading or trailing spaces. 
 
- How about multiple spaces between two words? 
Reduce them to a single space in the reversed string.

class Solution { 
public: 
    /** 
     * @param s : A string 
     * @return : A string 
     */ 
    string reverseWords(string s) { 
        if (s.empty()) { 
            return s; 
        } 
 
        string s_ret, s_temp; 
        string::size_type ix = s.size(); 
        while (ix != 0) { 
            s_temp.clear(); 
            while (!isspace(s[--ix])) { 
                s_temp.push_back(s[ix]); 
                if (ix == 0) { 
                    break; 
                } 
            } 
            if (!s_temp.empty()) { 
                if (!s_ret.empty()) { 
                    s_ret.push_back(' '); 
                } 
                std::reverse(s_temp.begin(), s_temp.end()); 
                s_ret.append(s_temp); 
            } 
        } 
 
        return s_ret; 
    } 
};

#include <iostream> 
#include <string> 
#include <cstdio> 
#include <sstream> 
#include <vector> 
 
using namespace std; 
 
int main(){ 
     
    string str = "The sky  is blue"; 
    cout<<"Origin string : "<<str<<endl; 
    vector<string> v; 
    stringstream input(str); 
    string temp; 
    while(input>>temp){ 
        v.push_back(temp); 
    } 
     
    for (int i=v.size()-1;i>0;i--) { 
        cout<<v[i]<<" "; 
    } 
    cout<<v[0]<<endl; 
    return 0; 
}

Origin string : The sky  is blue 
blue is sky The