using System;

namespace NeetaAssignment
{
    class FunctionCalculator
    {
        private double Lower;
        private double Upper;
        private int Steps;

        // Constructor Overriding

        public FunctionCalculator()
        {
        }

        public FunctionCalculator(double LowerLimit, double UpperLimit, int steps)
        {
            this.Lower = LowerLimit;
            this.Upper = UpperLimit;
            this.Steps = steps;
        }

        // Get and Set method for lower limit,upper limit and steps

        // get and return method for lower limit,upper limit,and steps
        public double getLowerLimit()
        {
            return this.Lower;
        }

        public double getUpperLimit()
        {
            return this.Upper;
        }
        public double getsteps()
        {
            return this.Steps;
        }

        // Set method for lower limit,upper limit,and steps

        public void setLowerLimit(double a)
        {
            this.Lower = a;
        }

        public void setUpperLimit(double b)
        {
            this.Upper = b;
        }

        public void setsteps(int c)
        {
            this.Steps = c;
        }


        //Now write method for given function which will return value

        public virtual double Funct(double X)
        {
            double function;
            function = 2 / (1 + 4 * X * X);
            return function;
        }


        double GetStepsize ()
        {
            double Stepssize =  ((Upper - Lower) / Steps);
            return Stepssize;
        }


        //one more method for integration as Simpson Calculation

        public double CalculateSimpson()
        {

            double Stepssize = GetStepsize ();
            double Simpson = 0;
            for (double i = Lower; i <= Upper; i = i + Stepssize)
            {

                double a = i;
                double b = i + Stepssize;
                Simpson = Simpson + ((b - a) / 6) * (Funct(a) + 4 * Funct((a + b) / 2) + Funct(b));


            }

            return Simpson;
        }


        public double CalculateMidpointRule()
        {
            double Stepssize = ((Upper - Lower) / Steps);
            double MidPoint = 0;
            for (double i = Lower; i <= Upper; i = i + Stepssize)
            {

                double a = i;
                double b = i + Stepssize;
                MidPoint = MidPoint + ((b-a) *  Funct((a + b) / 2));
            }
            return MidPoint;

        }
        public double CalculateTrapeziumRule()
        {
            double Stepssize = ((Upper - Lower) / Steps);
            double Trapezium = 0;
            for (double i = Lower; i <= Upper; i = i + Stepssize)
            {

                double a = i;
                double b = i + Stepssize;
                Trapezium = Trapezium + ((b - a) / 2)*(Funct(a) + Funct(b));
            }
            return Trapezium;

        }


        public void GetResult()
        {
            Console.WriteLine(" \n Lower Limit={0}\n upperlimit={1} \n Steps={2} \n ", Lower, Upper, Steps);
        }

    }

    class Class2 : FunctionCalculator
    {
        public override double Funct(double X)
        {
            double function;
            function = Math.Sin(X);
            return function;
        }
    }

    class MainClass
    {
        public static void Main (string[] args)
        {
            FunctionCalculator c = new FunctionCalculator();
            Console.WriteLine(" Enter Lower Limit");
            c.setlowerlimit(Convert.ToDouble(Console.ReadLine()));
            Console.WriteLine(" Enter Upper Limit");
            c.setupperlimit(Convert.ToDouble(Console.ReadLine()));
            Console.WriteLine(" Enter Steps");
            c.setsteps(Convert.ToDouble(Console.ReadLine()));
            double Simpson = c.CalculateSimpson();
            c.GetResult();
            Console.WriteLine("Simpson=" + Simpson);

            /*
            Class2 C1 = new Class2();
            Console.WriteLine(" Enter Lower Limit");
            C1.setlowerlimit(Convert.ToInt32(Console.ReadLine()));
            Console.WriteLine(" Enter Upper Limit");
            C1.setupperlimit(Convert.ToInt32(Console.ReadLine()));
            Console.WriteLine(" Enter Steps");
            C1.setsteps(Convert.ToInt32(Console.ReadLine()));
            double Simpson1 = C1.CalculateSimpson();
            C1.GetResult();
            Console.WriteLine("Simpson 1=" + Simpson1);
            */
        }
    }
}