Substring algorithm

Question

Can someone explain to me how to solve the substring problem iteratively?

The problem: given two strings S=S₁S₂S

Answer 1

Not sure what language you're working in, but here's an example in C#. It's a roughly n² algorithm, but it will get the job done.

bool IsSubstring (string s, string t)
{
   for (int i = 0; i <= (s.Length - t.Length); i++)
   {
      bool found = true;

      for (int j = 0; found && j < t.Length; j++)
      {
         if (s[i + j] != t[j])
             found = false;
      }

      if (found)
         return true;
   }

   return false;
}