import std.stdio, std.math, std.string, std.conv;

void main()
{
    double a, b, c;

    a = readDouble("a");
    b = readDouble("b");
    c = readDouble("c");

    writefln("Obliczam ax^2 + bx + c = 0");

    double delta = getDelta(a, b, c);
    writeln("Delta: ", delta);

    if(delta > 0) {
        double x1, x2;

        x1 = (-b - sqrt(delta)) / (2 * a);
        x2 = (-b + sqrt(delta)) / (2 * a);

        writeln("Znaleziono dwa rozwiazania: ");
        writeln("\tx1 = ", x1);
        writeln("\tx2 = ", x2);
    }
    else if(delta == 0) {
        double x;

        x = -b / (2 * a);

        writeln("Znaleziono jedno rozwiazanie: ");
        writeln("\tx = ", x);
    }
    else
        writeln("Brak rozwiazan.");

    readln();
}

double readDouble(string name) {
    string buffer;
    double d;

    while(true) {
        write("Podaj ", name, ": ");
        readf("%s\n", &buffer);

        buffer = buffer.replace(",", ".");

        try {
            d = buffer.to!double;
        }
        catch {
            writeln("To chyba nie jest liczba.");
            continue;
        }

        return d;
    }
}

double getDelta(double a, double b, double c) {
    return (b ^^ 2) - (4 * a * c);
}