using System;
using System.Collections.Generic;

namespace ConsoleApp4
{
    
    
    class Program
    {
    
    
        static void Main(string[] args)
        {
    
    
            //字典
            Dictionary<int, string> dic = new Dictionary<int, string>(10);
            dic.Add(2, "Java");
            dic.Add(1, "C#");
            dic.Add(0, "Go");
            dic.Add(4, "C++");
            dic.Add(3, "C");
            dic[7] = "python";
            dic[3] = "Php";
            //遍历
            foreach(var item in dic)
            {
    
    
                Console.WriteLine(item.Key + " " + item.Value);
            }
            foreach (var item in dic.Keys)
            {
    
    
                Console.WriteLine(dic[item]);
            }
            //键值对
            KeyValuePair<int, string> keyValuePair0 = new KeyValuePair<int, string>(3,"gogo");
            Console.WriteLine(keyValuePair0.Value);

            //统计字符串各符号出现次数
            String str = "good good study,day day up!";
            Dictionary<char, int> dict = new Dictionary<char, int>();
            for(int i = 0;i < str.Length; i++)
            {
    
    
                if (dict.ContainsKey(str[i]))
                {
    
    
                    dict[str[i]]++;
                }
                else
                {
    
    
                    //dict[str[i]] = 1;
                    dict.Add(str[i], 1);
                }
            }
            foreach (var item in dict)
            {
    
    
                Console.WriteLine(item.Key + " " + item.Value);
            }
        }
    }
}