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

namespace CourseWork_eko
{
    class Program
    {

// Задание 1

     static double[] xval       = new double[] { 0, 1.97, 3.91, 5.8, 6.22, 6.52, 6.87, 8.73, 10.73, 13.62, 15.4 }; // Олины циферки нужны
     static double[] yval       = new double[] { 800, 840, 880, 905, 970, 995, 1003, 1020, 1030, 1060, 1100 };
     static double[] abc     = new double[] { 0.0, 0.0, 0.0 };

     static double l = 1, tm0 = 20, tmk = 1400, c = 0.7 * 1000, R = 20.9 * 1000000, hi = 0.8;




    static double[] metzona1;
    static double[] metzona2; // Прилепишь третью зону также

     static double[,] matrix = new double[3, 3] ;
     static double[] rval       = new double[3];

     static void task1()
     {

         ///////////////Fill matrix with nulls //////////////////////
         for (int i = 0; i < 3; ++i)
             for (int j = 0; j < 3; ++j)
                 matrix[i, j] = 0;

         rval[0] = rval[1] = rval[2] = 0;
         ////////////////////////////////////////////////////////////

         int n = xval.Length;
         for (int i = 0; i < n; ++i)
         {
             double x = xval[i];
             ///////// Fill first line in matrix  //////////////////
             matrix[0, 0] += 1;
             matrix[0, 1] += Math.Tan(x / (1 + x));
             matrix[0, 2] += Math.Log(1 + x);
             ///////// Fill second line in matrix //////////////////   
             matrix[1, 0] += Math.Tan(x / (1 + x));
             matrix[1, 1] += Math.Tan(x / (1 + x)) * Math.Tan(x / (1 + x));
             matrix[1, 2] += Math.Log(1 + x) * Math.Tan(x / (1 + x));
             ///////// Fill third line in matrix  //////////////////
             matrix[2, 0] += Math.Log(1 + x);
             matrix[2, 1] += Math.Tan(x / (1 + x)) * Math.Log(1 + x);
             matrix[2, 2] += Math.Log(1 + x) * Math.Log(1 + x);
             ///////////////////////////////////////////////////////

             rval[0] += yval[i];
             rval[1] += yval[i] * Math.Tan(x / (1 + x));
             rval[2] += yval[i] * Math.Log(1 + x);
         }    

         n = rval.Length;
         for(int i = 0; i < n; ++i)
             for (int j = i + 1; j < n; ++j)
             {
                 double value = matrix[i, i];
                 double koeff = matrix[j, i] / value;
                 for (int c = 0; c < n; ++c)
                     matrix[j, c] -= koeff * matrix[i, c];
                 rval[j] -= koeff * rval[i];             
             }
          for (int i = n - 1; i >= 0; --i)
             for (int j = i - 1; j >= 0; --j)
             {
                 double value = matrix[i, i];
                 double koeff = matrix[j, i] / value;
                 for (int c = 0; c < n; ++c)
                     matrix[j, c] -= koeff * matrix[i, c];
                 rval[j] -= koeff * rval[i];
             }
          for (int i = 0; i < n; ++i)
          {
              abc[i] = rval[i] / matrix[i, i];            
          }     
     }    


        // First zone 0 <= x <= 15.4
     static double zona1(double x)
        {
            return abc[0] + abc[1] * Math.Tan(x / (1 + x)) + abc[2] * Math.Log(1 + x);  
        }

        // Second zone 15.4 < x <= 49.6
     static double zona2(double x)
     {
         return 365.861 - 5.697 * Math.Sin(x) + 258.083 * Math.Log(1 + x);     
     }


        // Сюда тоже уравнение ебалы для третей зоны она считается также как сдесь для первой а на место первой прикрутишь формулу


        /*/////////////////////////////////////////////////////////////////////////////////////////*/
        /* Задание 2 */
        /* *///////////


    

     static int steps = 100;

     delegate double solveFunc(double x);


     static double diffur(double x, double y)
     {
         return x - y;    
     }
     static void rungeKutta(double[] temp, solveFunc func, double a, double b)
     { 
        double h = (b - a) / steps;
        double x = a;
        double k1, k2, k3, k4;

        for (int i = 0; i < steps; ++i)
        {
            k1 = h * diffur(func(x), temp[i] );
            k2 = h * diffur(func(x + h / 2), temp[i] + k1 / 2 );
            k3 = h * diffur(func(x + h / 2), temp[i] + k2 / 2 );
            k4 = h * diffur(func(x + h), temp[i] + k3);
            temp[i + 1] = temp[i] + (k1 + 2 * k2 + 2 * k3 + k4) / 6;
            
            x += h;       

         }     
     }
        // Вот эту ебалу тоже поменять придется чтобы для трех зон работала
     static double currCons(double x)
     {
         if (x <= 15.4)
         {

             double tn = zona1(x);
             int index = (int)(x / (15.4 / steps));
             return (tn - metzona1[index]) / (tmk - tn);
         }
         else
         {
             double tn = zona2(x);
             int index = (int)( (x - 15.4) / ((49.6 - 15.4) / steps));
             return (tn - metzona2[index]) / (tmk - tn);         
         }
     }

        //* Вот эту херню перепелить полностью тебе не симпсон а трапеции нужны */

     static double simpson(double a, double b, int n)
     {
         double h = (b - a) / n;
         double s = currCons(a) + currCons(b);
         double x = a;
         int c = 1;
         for (int i = 1; i < n; ++i)
         {
             x = x + h;             
             s += (3 + c) * currCons(x);
             c = -c;         
         }
         return s * h / 3;  
     }



        


        static void Main(string[] args)
        {
         
            task1();

            metzona1 = new double[steps + 1];
            metzona2 = new double[steps + 1];
            metzona1[0] = tm0;
            rungeKutta(metzona1, zona1, 0, 15.4);
            metzona2[0] = metzona1[steps];
            rungeKutta(metzona2, zona2, 15.4, 49.6);

            // Сюда прилепишь считалку для третьей зоны

            Console.WriteLine("--------------Результаты вычислений-----------------");
            Console.WriteLine("Коэффициенты a,b,c: a = {0:F4}, b = {1:F4}, c = {2:F4}", rval[0], rval[1], rval[2]);
            Console.WriteLine("----Распределение температуры металла в печи--------");
            Console.WriteLine("------------------Первая зона-----------------------");
            double h = 15.4 / steps;
            double x = 0;
            for (int i = 0; i < metzona1.Length; ++i)
            {
                Console.WriteLine("x = {0:F4}  Temperature = {1:F4}", x, metzona1[i]);
                x += h;
            }
            x -= h;
            Console.WriteLine("------------------Вторая зона-----------------------");
            h = (49.6 - 15.4) / steps;
            for (int i = 0; i < metzona1.Length; ++i)
            {
                Console.WriteLine("x = {0:F4}  Temperature = {1:F4}", x, metzona2[i]);
                x += h;
            }
            
            double answer3 = tmk * c / (hi * R) * simpson(0, 49.6, 100);
            Console.WriteLine("Потребление топлива: {0:F4} ", answer3);
        }
    }
}