c#用Dictionary<char,int>来计算字符串中每种字母出现的次数（面试题）

static void Main(string[] args)
{

string msg = "wo xi huan ni bao bei？";
            msg=msg.ToLower();
            Dictionary<char,int> dick=new Dictionary<char,int>();   声明一个集合来统计
            for (int i = 0; i < msg.Length; i++)
            {                                                       循环字符串的每个字符来统计
                if (dick.ContainsKey(msg[i]))
                {
                    dick[msg[i]]++;
                }
                else
                {
                    dick.Add(msg[i], 1);
                }
            }
            foreach (KeyValuePair<char,int> item in dick)
            {
                Console.WriteLine("{0}字符的次数:{1}",item
                    .Key,item.Value);
            }
}