using System;

public class Program

{

    public static void Main()

    {

        int[] arr = { 10, 20, 30, 40, 50 };

        int target = 30;

        for(int i=0; i<arr.Length;i++)

        {

            if(arr[i] == target)

            {

                Console.WriteLine("Index of target " + target + " is " + i);

            }

        }

​

    }

}