using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace InStr

{

class Program

{

static void Main(string[] args)

{

//test case 1, should return -1

string txt = "this is a test";

string searchString = "ae";

Console.WriteLine(InStr(txt, searchString));

//cast case 2, should return 2

txt = "this is a test";

searchString = "is";

Console.WriteLine(InStr(txt, searchString));

Console.Read();

}

//return the position of the first occurrence of one

string "searchString" within another "txt"

//return -1 means cannot find

static int InStr(string txt, string searchString)

{

return txt.IndexOf(searchString);

}

}

}