LAB 4 Algo

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace zad1
{
    class Program
    {

        //y = x^2

        static float getFunc(float x)
        {
            return x * x;
        }




        static void Main(string[] args)
        {

            bool inputFlag = true;
            float a = 0, b = 0;

            Console.WriteLine("Vvedite a");
            while (inputFlag)
            {
                if (!float.TryParse(Console.ReadLine(), out a))
                {
                    Console.WriteLine("Error");
                    inputFlag = true;
                }
                else
                    inputFlag = false;
            }
            inputFlag = true;
            Console.WriteLine("Vvedite b");

            while (inputFlag)
            {
                if (!float.TryParse(Console.ReadLine(), out b))
                {
                    Console.WriteLine("Error");
                    inputFlag = true;
                }
                else
                    inputFlag = false;
            }

            Console.WriteLine("Интегралы от {0} до {1}:", a, b);
            Console.WriteLine("Метод прямоугольников: {0}", rectangleMethod(a, b));
            Console.WriteLine("Метод Монте-Карло: {0}", monteCarloMethod(a, b));
            Console.WriteLine("Метод трапеций: {0}", trapeziumMethod(a, b));
            Console.WriteLine("Метод Симпсона: {0}", simpsonMethod(a, b));


        }

        static float rectangleMethod(float a, float b)
        {
            float integral = 0;
            float step = 0.005f;
            for (float i = a; i <= b; i += step)
            {
                integral += getFunc(i);
            }
            integral *= step;
            return integral;
        }

        static float monteCarloMethod(float a, float b)
        {

            int isIn = 0;
            float maxYValue = getFunc(b), minYValue = getFunc(a);

            Random random = new Random(DateTime.Now.Millisecond);


            for (int i = 0; i < 300000; i++)
            {
                float pointX = GetRandomFloat(a, b, random);
                float pointY = GetRandomFloat(minYValue, maxYValue, random);
                if (getFunc(pointX) > pointY)
                    isIn++;
            }
            return (maxYValue * b * isIn)/300000;
        }

        static float trapeziumMethod(float a, float b)
        {
            float integral = 0;
            float step = 0.005f;
            for (float i = a; i <= b; i += step)
            {
                integral += 2 * getFunc(i);
            }
            integral = (integral + getFunc(a) + getFunc(b)) * step/2;
            return integral;
        }

        static float simpsonMethod(float a, float b)
        {
            int n = 1;
            float step = 0.005f;

            float integral = 0;
            float integral1 = 0, integral2 = 0;
            for (float i = a; i <= b; i += step)
            {
                if (n % 2 == 0)
                {
                    integral1 += getFunc(i);
                }
                else
                {
                    integral2 += getFunc(i);
                }
                n++;
            }
            integral = (integral + getFunc(a) + getFunc(b) + 4 * integral2 + 2*integral1) * step / 3;
            return integral;
        }

        public static float GetRandomFloat(float minimum, float maximum, Random random)
        {
            return (float) random.NextDouble() * (maximum - minimum) + minimum;
        }

    }
}