program.csharp

using System;

public class Program
{
    public static void Main(string[] args)
    {
        while (true)
        {
            Console.Write("Enter first number: ");
            int num1 = 0;
            while (!int.TryParse(Console.ReadLine(), out num1))
            {
                Console.WriteLine("Invalid input. Please enter a valid whole number.");
            }

            Console.Write("Enter second number: ");
            int num2 = 0;
            while (!int.TryParse(Console.ReadLine(), out num2))
            {
                Console.WriteLine("Invalid input. Please enter a valid whole number.");
            }

            string operation;

            while (true)
            {
                Console.Write("Choose operation (+,-,*,/,%,=): ");
                operation = Console.ReadLine();

                if (operation == "+" || operation == "-" || operation == "*" ||
                    operation == "/" || operation == "%" || operation == "=")
                {
                    break;
                }
                else
                {
                    Console.WriteLine("\nIncorrect Operation Used, please try again\n");
                }
            }

            if (operation == "=")
            {
                Console.WriteLine("\nProgram terminated.");
                break;
            }

            object result = Calculator.Calculate(num1, num2, operation);

            if (result != null)
            {
                Console.WriteLine($"\nResult: {result}\n");
            }
        }
    }
}