//подключение библиотек и заголовочных файлов
#include "Spline.h"
#include <iostream>
#include <cmath>

void cwert(double** mmm, double xxx, int row)
{
    double *alpha = new double[row-1];
    double *beta = new double[row-1];
    double *c = new double[row-1];
    double A, B, C, F, h, h1, z, D, e;

    alpha[0] = 0;
    beta[0] = 0;
    c[0] = 0;

    for (int i = 1; i < row-1; i++)
    {
        //вычисление коэффициентов полиномов
        h = mmm[0][i] - mmm[0][i - 1];
        h1 = mmm[0][i + 1] - mmm[0][i];
        A = h;
        B = 2.*(h + h1);
        C = h1;
        D = 6.*((mmm[1][i + 1] - mmm[1][i]) / h1 - (mmm[1][i] - mmm[1][i - 1]) / h);
        e = A*alpha[i - 1] + B;
        alpha[i] = -C / e;
        beta[i] = (D - A*beta[i - 1]) / e;
    }
    c[row - 1] = (D - A*beta[row - 2]) / (B + A*alpha[row - 2]);

    for (int i = row-2; i > 0; i--)
    {
        c[i] = alpha[i] * c[i + 1] + beta[i];
    }
}

double S(double** mmm, double xxx, int row, double *aa, double *bb, double *cc, double *dd)
{
    cwert(mmm, xxx, row);

    double S = 0;
    double h;
    for (int i = row-1; i >= 0; i--)
    {
        dd[i] = cc[i] = bb[i] = aa[i] = 0;
    }

    for (int i = row-1; i >= 0; i--)
    {
        h = mmm[0][i] - mmm[0][i - 1];
        aa[i] = mmm[1][i];
        dd[i] = (cc[i] - cc[i - 1]) / h;
        bb[i] = 0.5*h*cc[i] - (1 / 6.)*h*h*dd[i] + (mmm[1][i] - mmm[1][i - 1]) / h;
    }

    for (int i = 1; i < row-1; i++)
    {
        S = aa[i] + bb[i] * (xxx - mmm[i][0]) + (cc[i] / 2) * pow((xxx - mmm[i][0]), 2) + (dd[i] / 6) * pow((xxx - mmm[i][0]), 3);//вычисление по формуле
    }

    return S;
}

if (checkBox1->Checked)
{
    String^ Line;
    array<String^>^ strArr;
    array<Char>^ charArr = { ' ', 'n' };
    try
    {
        FileStream^ fs = gcnew FileStream("input.txt", FileMode::Open);
        StreamReader^ sr = gcnew StreamReader(fs, Encoding::UTF8);
        int i = 0;
        while (sr->EndOfStream != true)  // framework 2.0
        {
            sr->ReadLine();
            i++;
        }
        input->RowCount = i;
        i = 0;

        sr->DiscardBufferedData();
        sr->BaseStream->Seek(0, IO::SeekOrigin::Begin);
        while (sr->EndOfStream != true)  // framework 2.0
        {
            Line = sr->ReadLine();
            strArr = Line->Split(charArr);
            /*for (int i = 0; i < strArr->Length; i++)
            {
            MessageBox::Show(strArr[i]->Trim());
            }*/
            input->Rows[i]->Cells["X"]->Value = strArr[0]->Trim();
            input->Rows[i]->Cells["Y"]->Value = strArr[1]->Trim();
            //
            i++;
            //  MessageBox::Show(Convert::ToString(input->RowCount));
        }
        sr->Close();
    }
    catch (Exception^ ex) {
        //MessageBox::Show(ex->Message);
    }
}

private: System::Void button3_Click(System::Object^  sender, System::EventArgs^  e) {
    chart1->Series["Spline"]->Points->Clear();//очистка линий
    chart1->Series["Line"]->Points->Clear();//очистка линий

    if (checkBox1->Checked)
    {
        String^ Line;
        array<String^>^ strArr;
        array<Char>^ charArr = { ' ', 'n' };
        try
        {
            FileStream^ fs = gcnew FileStream("input.txt", FileMode::Open);
            StreamReader^ sr = gcnew StreamReader(fs, Encoding::UTF8);
            int i = 0;
            while (sr->EndOfStream != true)  // framework 2.0
            {
                sr->ReadLine();
                i++;

            }
            input->RowCount = i;
            i = 0;

            sr->DiscardBufferedData();
            sr->BaseStream->Seek(0, IO::SeekOrigin::Begin);
            while (sr->EndOfStream != true)  // framework 2.0
            {

                Line = sr->ReadLine();
                strArr = Line->Split(charArr);
            /*for (int i = 0; i < strArr->Length; i++)
            {
            MessageBox::Show(strArr[i]->Trim());
            }*/
                input->Rows[i]->Cells["X"]->Value = strArr[0]->Trim();
                input->Rows[i]->Cells["Y"]->Value = strArr[1]->Trim();
                //
                i++;
                //  MessageBox::Show(Convert::ToString(input->RowCount));
            }

            sr->Close();
        }
        catch (Exception^ ex) {
            //MessageBox::Show(ex->Message);
        }
    }

    int row = input->RowCount;//подстчет количество введеных данных

    double **mmm = new double *[row-1];//создание массива

    for (int i = 0; i < row-1; i++)
    {
        mmm[i] = new double[2];//в массиве 2 колонки
    }

    for (int i = 0; i < row-1; i++)
    {
        mmm[i][0] = Convert::ToDouble(input->Rows[i]->Cells["X"]->Value->ToString());//конвертировать строку в число
        mmm[i][1] = Convert::ToDouble(input->Rows[i]->Cells["Y"]->Value->ToString());

        if (checkBox3->Checked)
        {
            chart1->Series["Line"]->Points->Clear();//очистка линии сплайна
            chart1->Series["Spline"]->Points->AddXY(mmm[i][0], mmm[i][1]);//добавление на график точек
        }
    }

    double xxx, g;
    double *aa = new double[row-1];
    double *bb = new double[row-1];
    double *cc = new double[row-1];
    double *dd = new double[row-1];

    for (int i = 0; i < row-1; i++)
    {
        if (checkBox3->Checked)
        {
            xxx = mmm[i][2];
            g = S(mmm, xxx, row-1, aa, bb, cc, dd);//результат
            chart1->Series["Line"]->Points->Clear();
            chart1->Series["Spline"]->Points->AddXY(xxx, g);
            std::ofstream ff("cubic.txt", std::ios_base::out);
            if (ff.is_open())
            {
                ff << "Работа программы кубического сплайна :" << std::endl;
                ff << "результ. по точкам " << g << "n" << "время " << clock() / 1000.0 << std::endl;
                for (int i = 0; i < row-1; i++)
                {
                    //ff << "F(x)=" << i << " " << mmm[i][1] << "+" << mmm[i][2] << "+" << mmm[i][1] / 2 << "+" << mmm[i][1] / 6 << "+" << mmm[i][2];
                    ff << "F(x)=" << i << " ";//запись
                    ff << std::endl;
                    ff << mmm[i][0] << " " << mmm[i][1];//запись
                    ff << "n------------------rn" << " " << aa[i] << "+" << " " << bb[i] << "*" << " " << "(x - " << mmm[i][0] << ")" << " " << "+" << cc[i] << "*" << " " <<"(x - " << mmm[i][0] << ")^2" << " " << "+" << dd[i]/6. << "*" << " " << "(x - " << mmm[i][0] << ")^3";

                    ff << std::endl;
                }
                ff << std::endl;
                ff << "------------------nr" << std::endl;
            }
            else
                ff << errno;
            ff.close();
        }
    }
}