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.
题目大意：将一个字符串的每个单词反转～ 分析：将每个单词放入栈中，当遇到空格或者最后一个字符的时候，说明当前栈内为一个完整的单词，那么就将栈内的单词按字符一个个出栈加入result字符串中，根据flag的值判断是否是第一个单词，如果不是第一个单词就要在result的后面加一个空格～
class Solution { public: string reverseWords(string s) { string result = ""; stack<char> word; int flag = 0; for (int i = 0; i < s.length(); i++) { if (s[i] != ' ') word.push(s[i]); if (s[i] == ' ' || i == s.length() - 1) { if (flag == 1) result += " "; while (!word.empty()) { result += word.top(); word.pop(); flag = 1; } } } return result; } };