344. Reverse String

Write a function that takes a string as input and returns the string reversed.

Example:
Given s = "hello", return "olleh".

翻译：将给定字符串进行翻转，后输出翻转后的字符串。

例如：hello 变成olleh

class Solution{
public:
	void swap(char &a,char &b)
	{
		char temp=a;
		a=b;
		b=temp;
	}
	string reverseString(string s)
	{
		int len=s.size();
		int i=0;
		int j=len-1;
		while(i<j)
		{
			swap(s[i],s[j]);
			i++;
			j--;
		}
		return s;
	}
};