5 lab

using System;
using System.ComponentModel;
using System.IO;
using System.Windows.Forms;
using System.Windows.Forms.DataVisualization.Charting;

namespace Tabulation
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void textBox2_TextChanged(object sender, EventArgs e)
        {

        }

        private void textBox3_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "" || textBox2.Text == "" || textBox3.Text == "")
            {
                MessageBox.Show("Заполни все пустые поля", "Постой");
                return;
            }

            string Path = Application.StartupPath + @"\OUTPUT.txt";

            double a = Convert.ToDouble(textBox1.Text);
            double b = Convert.ToDouble(textBox3.Text);
            double h = Convert.ToDouble(textBox2.Text);

            if (a>b)
            {
                MessageBox.Show("Некорректное значение a или b", "Постой");
                return;
            }

            double y;

            FileStream file = new FileStream(Path, FileMode.OpenOrCreate);
            StreamWriter stream = new StreamWriter(file);

            stream.WriteLine("Тагирова Валерия \n!     X       !      Y       !");

            // График
            this.chart1.Series[0].Points.Clear();
            while (a<=b)
            {
                if (a >= 0)
                {
                    y = Math.Round(Math.Pow(a, 6.5) / Math.Exp(Math.Cos(a)), 3);
                    stream.WriteLine("!     " + a + "       !      " + y + "       !");
                    this.chart1.Series[0].Points.AddXY(a, y);
                }
                else
                {
                    stream.WriteLine("!     " + a + "       !      -       !");
                }
                a = Math.Round(a + h, 3);
            }

            chart1.SaveImage(Application.StartupPath + @"\OUTPUT.png", ChartImageFormat.Png);

            stream.Close();
            file.Close();
        }

        private void textBox1_KeyPress(object sender, KeyPressEventArgs e) //a
        {
            if (Char.IsNumber(e.KeyChar) || e.KeyChar == ',' || e.KeyChar == '\b' || e.KeyChar == '-') return;
            else
                e.Handled = true;
        }

        private void textBox2_KeyPress(object sender, KeyPressEventArgs e) //h
        {
            if (Char.IsNumber(e.KeyChar) || e.KeyChar == ',' || e.KeyChar == '\b') return;
            else
                e.Handled = true;
        }

        private void textBox3_KeyPress(object sender, KeyPressEventArgs e) //b
        {
            if (Char.IsNumber(e.KeyChar) || e.KeyChar == ',' || e.KeyChar == '\b' || e.KeyChar == '-') return;
            else
                e.Handled = true;
        }

        private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
        {

        }

        private void chart1_Click(object sender, EventArgs e)
        {

        }

        private void label3_Click(object sender, EventArgs e)
        {

        }

        private void label2_Click(object sender, EventArgs e)
        {

        }
    }


}