CODEWITHSUNDEEP
c#
Sleepless
Sleepless

Reputation: 103

Quadratic Equation Solver in C#

I'm trying to write a simple quadratic equation solver in C#, but for some reason it's not quite giving me the correct answers. In fact, it's giving me extremely large numbers as answers, usually well into the millions.

Could anyone please shed some light? I get the exact same answer for the positive root and the negative root as well. (Tried two different methods of math)

static void Main(string[] args)
    {
        int a;
        int b;
        int c;

        Console.WriteLine("Hi, this is a Quadratic Equation Solver!");
        Console.WriteLine("a-value: ");
        try
        {
            a = int.Parse(Console.ReadLine());
            Console.WriteLine("b-value: ");
            b = int.Parse(Console.ReadLine());
            Console.WriteLine("c-value: ");
            c = int.Parse(Console.ReadLine());
            Console.WriteLine("Okay, so your positive root is: " + quadForm(a, b, c, true));
            Console.WriteLine("And your negative root is: " + quadForm(a, b, c, false));
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
        Console.ReadLine();
    }

    static int quadForm(int a, int b, int c, Boolean pos)
    {
        int x = 0;
        if (pos)
            x = ((-b + (int) (Math.Sqrt((b * b) - (4 * a * c)))) / (2 * a));
        else
            x = ((-Math.Abs(b) - (int) (Math.Sqrt(Math.Pow(b,2) - (4 * a * c)))) / (2 * a));
        return x;
    }

Upvotes: 2

Views: 12786

Answers (1)

Enigmativity
Enigmativity

Reputation: 117029

Try this version of quadForm:

static double quadForm(int a, int b, int c, bool pos)
{
    var preRoot = b * b - 4 * a * c;
    if (preRoot < 0)
    {
        return double.NaN;
    }
    else
    {
        var sgn = pos ? 1.0 : -1.0;
        return (sgn * Math.Sqrt(preRoot) - b) / (2.0 * a);
    }
}

Upvotes: 4

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