C# Trapezoidal Rule

Implementation of Trapezoidal Rule (Integral Approximation) written in C#.

Enter beginning of interval: -2
Enter end of interval: 2
Enter number of iterations: 1000000
Integral is equal to: 5.33334933334409

using System;

// ? 2018 TheFlyingKeyboard and released under MIT License
// theflyingkeyboard.net
namespace Trapezoidal_Rule
{
    class Program
    {
        static void Main(string[] args)
        {
            double intervalBegin;
            double intervalEnd;
            int iterations;
            double integral;
            double step;

            Console.Write("Enter beginning of interval: ");
            intervalBegin = Convert.ToDouble(Console.ReadLine());

            Console.Write("Enter end of interval: ");
            intervalEnd = Convert.ToDouble(Console.ReadLine());

            Console.Write("Enter number of iterations: ");
            iterations = Convert.ToInt32(Console.ReadLine());

            step = (intervalEnd - intervalBegin) / iterations;
            integral = 0.5 * (function(intervalBegin) + function(intervalEnd));

            for (int i = 0; i < iterations; ++i)
            {
                integral += function(intervalBegin + step * i);
            }

            integral *= step;

            Console.WriteLine("Integral is equal to: " + integral);
            Console.ReadKey();
        }

        private static double function(double x)
        {
            return x * x;
        }
    }
}