LeetCode 151. Reverse Words in a String

151. 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".

分析：我用的方法是把字符串中的所有单词放入栈里，然后将栈里的所有字符串弹栈到字符串s中～

class Solution {public:    void reverseWords(string &s) {        stack<string> sstack;        int flag = 0;        string temp = "";        for(int i = 0; i < s.length(); i++) {            if(s[i] != ' ' && flag == 0) {                temp = "";                temp += s[i];                flag = 1;            } else if(s[i] != ' ') {                temp += s[i];            } else if(s[i] == ' ' && flag == 1){                sstack.push(temp);                flag = 0;            }            if(i == s.length() - 1 && flag == 1)                sstack.push(temp);        }        s = "";        while(!sstack.empty()) {            string temp = sstack.top();            s += temp;            sstack.pop();            if(!sstack.empty())                s += " ";        }    }};