C#计算每个字符的出现次数

using System;

public class Demo {
   public static void Main() {
      string str = Website;

      Console.WriteLine(String: +str);

      while (str.Length > 0) {
         Console.Write(str[0] +  = );
         int cal = 0;

         for (int j = 0; j < str.Length; j++) {
            if (str[0] == str[j]) {
               caL++;
            }
         }

         Console.WriteLine(cal);
         str = str.Replace(str[0].ToString(), string.Empty);
      }
      Console.ReadLine();
   }
}