private static void NumberProcessing(Calculator calculator, string input)
{
calculator.Clear();
double firstNum = double.Parse(input);
string operation = Console.ReadLine();
double secondNum = double.Parse(Console.ReadLine());
switch (operation)
{
case "+":
calculator.Add(firstNum, secondNum);
break;
case "-":
calculator.Subtract(firstNum, secondNum);
break;
case "*":
calculator.Multiply(firstNum, secondNum);
break;
case "/":
calculator.Division(firstNum, secondNum);
break;
}
Console.WriteLine($"The result is: {calculator.FinalResult()}");
}