My first "real" program that was not on a TI-83. Written in C# on my first laptop during the summer of 2009.

QuadForm.cs

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

public class QuadForm
{
    static void Main(string[] args)
    {
        Console.WriteLine("Welcome to the Quadratic Formula Program!");
        Console.WriteLine("Equation: ax² + bx + c = 0");
        Console.WriteLine("Formula: x = (-b ± √(b² - 4*a*c))/(2*a)");
        InputWrapper iw = new InputWrapper();
        double a, b, c, d;
        int i = 0;
        a = iw.getDouble("a: ");
        b = iw.getDouble("b: ");
        c = iw.getDouble("c: ");
        d = b*b-(4*a*c);
        a = 2 * a;
        if (d < 0)
        {
            i = 1;
            d = 0 - d;
        }
        double e = 2;
        double f = 1;
        while (Math.Pow(e, 2) < d)
        {
            if (Math.IEEERemainder(d , Math.Pow(e, 2)) == 0)
            {
                d = d / Math.Pow(e, 2);
                f = e * f;
                e = e - 2 + Convert.ToDouble(e == 3);
            }
            e = e + 2 - Convert.ToDouble(e == 2);
        }
        double g;
        e = 2;
        g = Math.Max(b, f);
        g = Math.Max(a, g);
        while (e <= g)
        {
            if (Math.IEEERemainder(b, e) == 0 & (Math.IEEERemainder(f, e) == 0 | f == 1) & Math.IEEERemainder(a, e) == 0)
            {
                b = b / e;
                if (f != 1)
                {
                    f = f / e;
                }
                a = a / e;
                e = e - 2 + Convert.ToDouble(e == 3);
            }
            e = e + 2 - Convert.ToDouble(e == 2);
        }
        if (d == 0)
        {
            Console.WriteLine("Only one answer:");
            if (a > 1)
            {
                Console.WriteLine("{0} / {1}", 0 - b, a);
            }
            if (a == 1)
            {
                Console.WriteLine("{0}", 0 - b);
            }
            Console.ReadLine();
            return;
        }
        if (d > 1)
        {
            if (a > 1)
            {
                Console.Write("(");
            }
            if (b != 0)
            {
                Console.Write("{0} ± (", 0 - b);
            }
            if (f > 1)
            {
                Console.Write("{0}*", f);
            }
            if (i == 1)
            {
                Console.Write("i*");
            }
            Console.Write("√({0})", d);
            if (a > 1)
            {
                Console.Write(") / ({0})", a);
            }
        }
        Console.WriteLine("\nEnd of Program!");
        Console.ReadLine();
        return;
    }

    // Definition for InputWrapper Class
    //
    // Class to wrap simple stream input
    // Datatype supported:
    //      int
    //      double
    //      decimal
    //      string
    public class InputWrapper
    {
        public int getInt(string prompt)
        {
            Console.Write(prompt);
            string buf = Console.ReadLine();
            return Convert.ToInt32(buf);
        }
        public double getDouble(string prompt)
        {
            Console.Write(prompt);
            string buf = Console.ReadLine();
            return Convert.ToDouble(buf);
        }
        public decimal getDecimal(string prompt)
        {
            Console.Write(prompt);
            string buf = Console.ReadLine();
            return Convert.ToDecimal(buf);
        }
        public string getString(string prompt)
        {
            Console.Write(prompt);
            string buf = Console.ReadLine();
            return buf;
        }
    }
}