C# Program to Perform All Arithmetic Operations

using System;

class Program
{
    static void Main()
    {
        double num1, num2;
        char operatorSymbol;

        Console.WriteLine("Arithmetic Operations Program");
        Console.WriteLine("=============================");
        Console.Write("Enter the first number: ");
        num1 = GetValidNumber();

        Console.Write("Enter the second number: ");
        num2 = GetValidNumber();

        Console.Write("Enter the operator (+, -, *, /): ");
        operatorSymbol = GetValidOperator();

        double result = 0.0;

        switch (operatorSymbol)
        {
            case '+':
                result = num1 + num2;
                break;
            case '-':
                result = num1 - num2;
                break;
            case '*':
                result = num1 * num2;
                break;
            case '/':
                if (num2 == 0)
                {
                    Console.WriteLine("Error: Division by zero is not allowed.");
                    return;
                }
                result = num1 / num2;
                break;
            default:
                Console.WriteLine("Invalid operator entered.");
                return;
        }

        Console.WriteLine($"Result: {num1} {operatorSymbol} {num2} = {result}");
    }

    static double GetValidNumber()
    {
        double number;
        while (!double.TryParse(Console.ReadLine(), out number))
        {
            Console.Write("Invalid input. Please enter a valid number: ");
        }
        return number;
    }

    static char GetValidOperator()
    {
        char[] validOperators = { '+', '-', '*', '/' };
        char operatorSymbol;
        while (!char.TryParse(Console.ReadLine(), out operatorSymbol) || Array.IndexOf(validOperators, operatorSymbol) == -1)
        {
            Console.Write("Invalid input. Please enter a valid operator (+, -, *, /): ");
        }
        return operatorSymbol;
    }
}