Mishvaha Ribuit Solver *Ron Serruya*

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Misvaha_Ribuit_Slover
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        decimal a, b, c, Delta, X1, X2, Delta_Sqrt1, X_kodkod, Y_kodkod;
        double Delta_Sqrt;
        private void Num_A_ValueChanged(object sender, EventArgs e)
        {
            if (Num_A.Value == 0)
                Num_A.ForeColor = System.Drawing.Color.Red;
            else
                Num_A.ForeColor = System.Drawing.SystemColors.WindowText;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                a = Num_A.Value;
                b = Num_B.Value;
                c = Num_C.Value;
                if (a == 0)
                    MessageBox.Show("a cannot be 0");
                else
                {
                    Delta = b * b - 1 * (4) * (a) * (c);
                    textBox_Solution.Text = "▲ = " + b.ToString() + "² " + "-4 * " + a.ToString() + " * " + c.ToString();
                    textBox_Solution.Text += "\r\n▲ = " + Delta.ToString();
                    Delta_Sqrt = Math.Sqrt((double)Delta);
                    textBox_Solution.Text += "\r\n√" + Delta.ToString() + " = " + Delta_Sqrt.ToString();

                    X_kodkod = (b * (-1)) / (2 * a);            /*חישוב נקודת קודקוד*/
                    Y_kodkod = (Delta * (-1)) / (4 * a);
                    textBox_Kodkod.Text = "( " + X_kodkod.ToString() + ", " + Y_kodkod.ToString() + " )";

                    if (b >= 0)                                 /* חישוב ניגזרת */
                    textBox_Nigzeret.Text = "Y' = " +(2 * a).ToString() + "X + " + b.ToString();
                    else
                    textBox_Nigzeret.Text = "Y' = " + (2 * a).ToString() + "X " + b.ToString();

                    if(a > 0)                                  /* עלייה או ירידה */
                    textBox_upORdown.Text = "עולה";
                    if (a < 0)
                    textBox_upORdown.Text = "יורדת";

                    if (Delta < 0)                             /* פתירת המשוואה הריבועית */
                    textBox_Solution.Text += "\r\nאין פיתרון!";
                    if (Delta == 0)
                    {
                        textBox_Solution.Text += "\r\nX1,2 = (" + (b * -1).ToString() + " ± 0) /" + (2 * a).ToString();
                        X1 = (b * -1) / (2 * a);
                        textBox_Solution.Text += "\r\nX = " + X1.ToString();
                        textBox_X1.Text = "X1 = " + X1.ToString();
                    }
                    if (Delta > 0)
                    {
                        textBox_Solution.Text += "\r\nX = (" + (b * -1).ToString() + " ± " + Delta_Sqrt.ToString() + ") /" + (2 * a).ToString();
                        Delta_Sqrt1 = (decimal)Delta_Sqrt;
                        X1 = ((b * -1) + Delta_Sqrt1) / (2 * a);
                        X2 = ((b * -1) - Delta_Sqrt1) / (2 * a);
                        textBox_Solution.Text += "\r\nX1 = " + X1.ToString();
                        textBox_X1.Text = "X1 = " + X1.ToString();
                        textBox_Solution.Text += "\r\nX2 = " + X2.ToString();
                        textBox_X2.Text = "X2 = " + X2.ToString();
                    }

                    if (a < 0 && Y_kodkod < 0)              /* מציאת תחום שליליות וחיוביות */
                    {
                        textBox_Up_Point.Text = "אין";
                        textBox_Down_Point.Text = "כל X";
                        textBox_Down.Text = "X<" + X_kodkod.ToString("0.###");
                        textBox_Up.Text = "X>" + Y_kodkod.ToString("0.###");
                    }
                    if (a < 0 && Y_kodkod > 0)
                    {
                        textBox_Up_Point.Text = X1.ToString("0.###") + "<X<" + X2.ToString("0.###");
                        textBox_Down_Point.Text = X1.ToString("0.###") + ">X>" + X2.ToString("0.###");
                        textBox_Down.Text = "X<" + X_kodkod.ToString("0.###");
                        textBox_Up.Text = "X>" + Y_kodkod.ToString("0.###");
                    }
                    if (a < 0 && Y_kodkod == 0)
                    {
                        textBox_Up_Point.Text = "אין";
                        textBox_Down_Point.Text = "x<" + X1.ToString("0.###") + "<x";
                        textBox_Down.Text = "X<" + X_kodkod.ToString("0.###");
                        textBox_Up.Text = "X>" + Y_kodkod.ToString("0.###");
                    }
                    if (a > 0 && Y_kodkod > 0)
                    {
                        textBox_Up_Point.Text = "כל X";
                        textBox_Down_Point.Text =  "אין";
                        textBox_Down.Text = "X>" + X_kodkod.ToString("0.###");
                        textBox_Up.Text = "X<" + Y_kodkod.ToString("0.###");
                    }
                    if (a > 0 && Y_kodkod < 0)
                    {
                        textBox_Up_Point.Text = X1.ToString("0.###") + ">X>" + X2.ToString("0.###");
                        textBox_Down_Point.Text = X1.ToString("0.###") + "<X<" + X2.ToString("0.###");
                        textBox_Down.Text = "X>" + X_kodkod.ToString("0.###");
                        textBox_Up.Text = "X<" + Y_kodkod.ToString("0.###");
                    }
                    if (a > 0 && Y_kodkod == 0)
                    {
                        textBox_Up_Point.Text = "x<" + X1.ToString("0.###") + "<x";
                        textBox_Down_Point.Text = "אין";
                        textBox_Down.Text = "X>" + X_kodkod.ToString("0.###");
                        textBox_Up.Text = "X<" + Y_kodkod.ToString("0.###");
                    }

                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error [ " + ex.Message + " ]");
            }


        }

    }
}