How to find Missing Element in Series(1, 3, 5, 9, 11).

How to find Missing Element in Series(1, 3, 5, 9, 11).

Main Program

using System;
namespace DotNetByPriyanshu
{
    class Program
    {
        static void Main(string[] args)
        {

            int[] Series1 = { 1, 3, 5, 9, 11 }; // Output : 7
            int[] Series2 = { 2, 4, 6, 10, 12 }; // Output : 8

            // creating an object of missingElement  Class
            missingElement missingElement = new missingElement();

            int result1 = missingElement.Missing(Series1.Length, Series1);
            Console.WriteLine("Missing Element  for Series1= " + result1);

            int result2 = missingElement.Missing(Series2.Length, Series2);
            Console.WriteLine("Missing Element  for Series2= " + result2);

            Console.ReadLine();
        }
    }
}

Method:

namespace DotNetByPriyanshu

{

    public class missingElement

    {

        public int Missing(int size, int[] Array)

        {

            //Arithmetic Series sum of sequence.

            //sn=n/2[2a+(n-1)d]

            //sumOfSeries=1+3+5+9+11;

            //MissingNumber=sn-sumOfSeries.

            int MissingNumber = 0;

            int n = Array.Length + 1;

            int d = Array[1] - Array[0];

            int sn = n / 2 * (2 * Array[0] + (n - 1) * d);  // Formula

            // Sum of array.

            int sumOfArray = 0;

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

            {

                sumOfArray = sumOfArray + Array[i];

            }

           // Calculate Missing Element.

            MissingNumber = sn - sumOfArray;

            return MissingNumber;

        }

    }

}

Output:

 Series1= { 1, 3, 5, 9, 11 }; // Output : 7
 Series2= { 2, 4, 6, 10, 12 }; // Output : 8