string letters = "abcdefghijklmabcdefghijklm";
string output = "";
// test IndexOf to locate a substring in a string
output += "\n\n\"def\" is located at" + " index " + letters.IndexOf( "def" );
output += "\n\"def\" is located at index " + letters.IndexOf( "def", 7 );
output += "\n\"hello\" is located at index " + letters.IndexOf( "hello", 5, 15 );
System.Console.WriteLine(output);
