LAB 4 Algo v 1.1 (GOVNO)

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

namespace zad1
{
    class Program
    {



        static float getFunc(float x)
        {
            //Set func there
            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));
            MonteCarlosMethod();

        }

        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);
            int n = 10000;
            Random random = new Random(DateTime.Now.Millisecond);
            Random rnd = new Random(DateTime.Now.Hour);

            for (int i = 0; i < n; i++)
            {
                float pointX = GetRandomFloat(a, b, random);
                float pointY = GetRandomFloat(minYValue, maxYValue, rnd);
                Console.WriteLine("x = {0}, y = {1}", pointX, pointY);
                if (getFunc(pointX) > pointY)
                    isIn++;
            }
            return (maxYValue * b * isIn)/n;
        }

        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;
        }

        public static void MonteCarlosMethod()
        {
            double leftEdge, rightEdge, step;
            Console.WriteLine("enter left edge");
            leftEdge = double.Parse(Console.ReadLine());
            Console.WriteLine("enter right edge");
            rightEdge = double.Parse(Console.ReadLine());
            Console.Write("enter number of dots to count on\nn: ");
            int n = int.Parse(Console.ReadLine());
            double height = Math.Pow(rightEdge, 2);
            Random xRandom = new Random(DateTime.Now.Millisecond);
            Random yRandom = new Random(DateTime.Now.Hour);
            double xTemp, yTemp;
            double isInFunction = 0;
            for (int i = 0; i < n; i++)
            {
                xTemp = xRandom.NextDouble() * (rightEdge - leftEdge) + leftEdge;
                yTemp = yRandom.NextDouble() * height;
                if (yTemp < Math.Pow(xTemp, 2))
                    isInFunction++;
            }
            double result = ((rightEdge - leftEdge) * height) * (isInFunction / n);
            Console.WriteLine("result: " + result);
            Console.WriteLine("press any key to continue");
            Console.ReadKey();


        }

    }
}