Valid Parentheses

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.

#include<iostream>
#include<vector>
#include<string>
#include<stack>
using namespace std;

bool isValid(string s) {
	if (s.empty())
		return true;
	stack<char>CharStack;
	for (int i = 0; i != s.size();++i){
		if (s[i] == '(' || s[i] == '{' || s[i] == '[')
			CharStack.push(s[i]);
		else
		{
			if (CharStack.empty())
				return false;
			switch (s[i])
			{
			case ')':
				if (CharStack.top() == '(')
					CharStack.pop();
				else
					return false;
				break;
			case ']':
				if (CharStack.top() == '[')
					CharStack.pop();
				else
					return false;
				break;
			case'}':
				if (CharStack.top() == '{')
					CharStack.pop();
				else
					return false;
				break;
			default:
				break;
			}
		}
	}
	return CharStack.empty();
}