c# - 显示字符以及它们出现了多少次？

Question

我从用户那里得到一个字符串，然后把它放在一个字符数组中。现在我想显示字符串中的所有字符以及它们出现的次数。我的代码如下 请纠正我？

 using System;
 class count
 {
    public void charcount()
    {
       int i ;
       int count = 0;
       string s;
       Console.WriteLine("Enter the String:");
       s = Console.ReadLine();
       char[] carr = s.ToCharArray();
       for(i = 0; i < carr.Length; i++)
       {
         for(int j = 1; j < carr.Length; j++)
             {
               if(carr[j] == carr[i])
                       {
                count++;
                   }
                   else
                       {
                    return;
               }
               Console.WriteLine("The Character " + carr[i] + " appears " + count);
         }
       }        
    }

    static void Main()
    {
       count obj = new count();
       obj.charcount(); 
    }
  }

Answer 1

好吧，由于您没有构建唯一字符列表，您的代码至少会出现问题，您会在原始字符串中找到它们。任何包含多次出现的字符的字符串都会显示奇怪的结果。

这是一个为您计算信息的 LINQ 表达式(您可以在 LINQPad 中运行它以立即查看结果):

void Main()
{
    string s = "This is a test, with multiple characters";
    var statistics =
        from c in s
        group c by c into g
        select new { g.Key, count = g.Count() };
    var mostFrequestFirst =
        from entry in statistics
        orderby entry.count descending
        select entry;
    foreach (var entry in mostFrequestFirst)
    {
        Debug.WriteLine("{0}: {1}", entry.Key, entry.count);
    }
}

输出:

 : 6 <-- spacet: 5i: 4s: 4h: 3a: 3e: 3l: 2c: 2r: 2T: 1,: 1w: 1m: 1u: 1p: 1

If you can't use LINQ, here's an example that doesn't use that:

void Main()
{
    string s = "This is a test, with multiple characters";
    var occurances = new Dictionary<char, int>();
    foreach (char c in s)
    {
        if (occurances.ContainsKey(c))
            occurances[c] = occurances[c] + 1;
        else
            occurances[c] = 1;
    }
    foreach (var entry in occurances)
    {
        Debug.WriteLine("{0}: {1}", entry.Key, entry.Value);
    }
}