private static void Calculate()
{
Console.WriteLine("Enter expression to calculate:");
string input = Console.ReadLine();
List <string> convertFromInfixToPostfix = ShuntingYard.Convert(input);
Console.WriteLine("\nExpression in postfix: {0}", string.Join(" ", convertFromInfixToPostfix));
double result = RpnAlgorithm.Calculate(convertFromInfixToPostfix);
Console.WriteLine("\nResult = {0}", result);
}