Using Operators

using System;

namespace numbers
{
    class Program
    {
        public static void Main(string[] args)
        {
            int firstNumber = int.Parse(Console.ReadLine());
            int secondNumber = int.Parse(Console.ReadLine());
            char operatorUsed = char.Parse(Console.ReadLine());

            double sum = 0.0;

            if (secondNumber == 0 && operatorUsed == '/')
            {
                Console.WriteLine("Cannot divide {0} by zero", firstNumber);
            }
            else
            {
                switch (operatorUsed)
                {
                    case '+': Console.WriteLine("{0} {1} {2} = {3} - {4}", firstNumber, operatorUsed, secondNumber, sum = (firstNumber + secondNumber), sum % 2 == 0 ? "even" : "odd"); break;
                    case '-': Console.WriteLine("{0} {1} {2} = {3} - {4}", firstNumber, operatorUsed, secondNumber, sum = (firstNumber - secondNumber), sum % 2 == 0 ? "even" : "odd"); break;
                    case '*': Console.WriteLine("{0} {1} {2} = {3} - {4}", firstNumber, operatorUsed, secondNumber, sum = (firstNumber * secondNumber), sum % 2 == 0 ? "even" : "odd"); break;
                    case '%': Console.WriteLine("{0} % {1} = {2}", firstNumber, secondNumber, sum = (firstNumber % secondNumber)); break;
                    case '/': Console.WriteLine("{0} / {1} = {2}", firstNumber, secondNumber, sum = ((double)firstNumber / (double)secondNumber)); break;
                }
            }

        }
    }
}