static void Main(string[] args)
{
Calcul calculation = new Calcul();
Console.WriteLine("Hello! This app can help you solve a quadratic equation");
Console.WriteLine("Plese, put Enter from start");
while (Console.ReadLine() != "exit")
{
Console.WriteLine("Write a");
double a = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("Write b");
double b = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("Write c");
double c = Convert.ToDouble(Console.ReadLine());
calculation.printRoots(a, b, c);
Console.WriteLine("If you want close console put enter and write exit");
Console.ReadKey();
Console.Clear();
}
}