C#删除相邻重复字符

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

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Console.Write("输入一串字符:");
string str=Console.ReadLine();

for (int i = 1; i < str.Length; i++)
{
if (str[i - 1] == str[i])
{
str=str.Remove(i,1);
}
}
Console.WriteLine("{0}", str);
Console.Read();
}
}
}

string a="aakmjjhjjjjwwws";

StringBuilder sb=new StringBuilder();

for(int i=0;i<a.Length;i++)

{

if(a[(i+1)%a.Length]!=a[i%a.Length])

sb.Append(a[i]);

}

Console.WriteLine (sb.ToString());