question:
Write a function that takes a string as input and returns the string reversed.
Example:
Given s = "hello", return "olleh".
answer：
交换字符串中的元素
class Solution { public: string reverseString(string s) { int l = s.length(); int i; char tem; for(i=0;i<l/2;i++){ tem = s[i]; s[i] = s[l-1-i]; s[l-1-i] = tem; } return s; } };
原文：http://www.cnblogs.com/Reindeer/p/5624687.html