using System;

string DoSomething(byte[] bytes, int last ) 

{  

   string returnString = " ";  

​

   for (int ctr = 0; ctr <= last - 1; ctr++)  

   {  

     if (ctr % 20 == 0)  

        returnString += "\n ";  

​

     returnString += String.Format("{0:X2} ", bytes[ctr]);  

   } 

​

   return returnString;  

}