Program to Implement string.Contains() Functionality

namespace StringMatching
{
   class Program
   {
         static void Main(string[] args)
         {
                     Console.WriteLine("Enter the string");
                     string s1 = Convert.ToString(Console.ReadLine()).Trim().ToUpper();
                     Console.WriteLine("Enter the string to be search");
                     string s2 = Convert.ToString(Console.ReadLine()).Trim().ToUpper();
                     int sourceIndex = 0;
                     int searcIndex = 0;
                     bool searchResult = false;
                     int matchingCount = 0;
                     while (sourceIndex < s1.Length)
                     {
                           if (s2[searcIndex].Equals(s1[sourceIndex]))
                           {
                                 searcIndex++;
                                 sourceIndex++;
                                 searchResult = true;
                                 matchingCount++;
                                 if(matchingCount == s2.Length)
                                {
                                       break;
                                 }
                            }
                          else
                           {
                                 searcIndex=0;
                                 sourceIndex++;
                                 searchResult = false;
                           }
                        if (sourceIndex == s1.Length) searchResult = false;
                     }
                     if(searchResult)
                     {
                           Console.WriteLine("Searching string is found");
                     }
                     else
                     {
                           Console.WriteLine("Searching string is not found");
                     }
                     Console.ReadLine();
      }
   }
}