using System;

​

namespace Better_Calculator

{

    public class Program

    {

        // I didn't use single line if else statements because I thought it would be easier to read

        static int Add(int num1, int num2)

        {

            return num1 + num2;

        }

​

        static int Subtract(int num1, int num2)

        {

            return num1 - num2;

        }

​

        static int Multiply(int num1, int num2)

        {

            return num1 * num2;

        }

​

        static string Divide(int num1, int num2)

        {

            if (num2 == 0)

            {

                Console.WriteLine("Cannot divide by zero.");

                return null;

            }

​

            int quotient = num1 / num2;

            int remainder = num1 % num2;

            return $"{quotient}r{remainder}";

        }

​

        static void Main(string[] args)

        {

            string input = "";

​

            while (input != "q" && input != "quit")

            {

                int num1 = ReadInt("Enter the first number:");

                int num2 = ReadInt("Enter the second number:");

​

                Console.WriteLine("Choose an operation (1 for add, 2 for subtract, 3 for multiply, 4 for divide):");

​

                int operation;

                try

                {

                    operation = int.Parse(Console.ReadLine());

                }

                catch (FormatException)

                {

                    Console.WriteLine("Invalid operation. Please enter a valid integer.");

                    continue;

                }

​

                string result;

​

                if (operation == 1)

                {

                    result = Add(num1, num2).ToString();

                }

                else if (operation == 2)

                {

                    result = Subtract(num1, num2).ToString();

                }

                else if (operation == 3)

                {

                    result = Multiply(num1, num2).ToString();

                }

                else if (operation == 4)

                {

                    Console.WriteLine("Do you want the result as a decimal (d) or a remainder (r)?");

                    string formatInput = Console.ReadLine();

​

                    if (formatInput != "d" && formatInput != "r")

                    {

                        Console.WriteLine("Invalid format. Please enter 'd' or 'r'.");

                        continue;

                    }

​

                    if (formatInput == "d")

                    {

                        double quotient = (double)num1 / num2;

                        result = quotient.ToString();

                    }

                    else if (formatInput == "r")

                    {

                        result = Divide(num1, num2);

                    }

                }

                else

                {

                    Console.WriteLine("Invalid operation. Please enter a valid integer between 1 and 4.");

                    continue; // go back to the start of the loop

                }

​

                Console.WriteLine("Result: " + result);

​

                Console.WriteLine("Press q or quit to exit, or any other key to continue:");

                input = Console.ReadLine();

            }

        }

​

        static int ReadInt(string prompt)

        {

            Console.WriteLine(prompt);

            string inputStr = Console.ReadLine();

            int input;

            try

            {

                input = int.Parse(inputStr);

            }

            catch (FormatException)

            {

                Console.WriteLine("Invalid input. Please enter a valid integer.");

                input = ReadInt(prompt); // recursively call ReadInt until a valid integer is entered

            }

            return input;

        }

    }

}

​