Program:

The source code to find the sum of array elements using the predefine method is given below. The given program is compiled and executed successfully on Microsoft Visual Studio.

//C# program to find the sum of array element 
//using Sum() method of Queryable class.

using System;
using System.Linq;

class Sample
{
    static void Main()
    {
        int[] MyArray = { 40, 30, 20, 10, 50 };
        int sum = 0;
        
        sum = Queryable.Sum(MyArray.AsQueryable());

        Console.WriteLine("Sum of array elements: {0}", sum);
    }
}

Output:

Sum of array elements: 150
Press any key to continue . . .

Explanation:

In the above program, we created an array of integers. Then find the sum of all array elements using the Sum() method of Queryable class. The Sum() method returns an integer value. To use a Queryable class, we need to import the System.Linq method in our program.