C#面试题统计用户输入的一串数字中每个数字出现的次数

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _2._22zuoye2
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("请输入一串数字");
            string str=Console.ReadLine();
            int l = str.Length;
            System.Console.WriteLine("您总共输入的字符数：{0}", l);
            for (int j = 0; j < l; j++)
            {
                string S = str.Substring(j, 1);
                if (str.IndexOf(S, 0, j) == -1)              //含有返回0,不含有返回-1;
                {
                    int m = 0;
                    for (int k = j; k < l; k++)
                    {
                        if (str.Substring(k, 1) == S)
                        {
                            m = m + 1;
                        }
                    }

                    System.Console.WriteLine("您输入字符“{0}”有{1}个", S, m);
                }
            }

            System.Console.ReadLine();

        }
    }
}