static void Main(string[] args)
{
var calculator = new Calculator();
double result = 0;
result = calculator.Add(5);
Console.WriteLine(result);
result = calculator.Add(4);
Console.WriteLine(result);
result = calculator.Add(3);
Console.WriteLine(result);
result = calculator.Minus(8);
Console.WriteLine(result);
result = calculator.Mult(5);
Console.WriteLine(result);
result = calculator.Minus(3);
Console.WriteLine(result);
result = calculator.Division(2);
Console.WriteLine(result);
/*result = calculator.Redo(1);
* Console.WriteLine(result);
*
* result = calculator.Undo(1);
* Console.WriteLine(result);*/
}