using System;

public class Program {

    public static void Main() {

        //attributes

        int numOne;

        int numTwo;

        int answer;

        string operation;

        Console.WriteLine("This is a basic calculator!!!");

        Console.WriteLine("");

        Console.WriteLine("Please enter the first number: ");

        numOne = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("Choose operation: (+, -, x, /) ");

        operation = Console.ReadLine();

        Console.WriteLine("Please enter the second number: ");

        numTwo = Convert.ToInt32(Console.ReadLine());

            if (operation == "+"){

                answer = numOne + numTwo;

                Console.WriteLine(numOne + " + " + numTwo + " is " + answer);

                Console.ReadLine();

            }

                else if (operation == "-"){

                    answer = numOne - numTwo;

                    Console.WriteLine(numOne + " - " + numTwo + " is " + answer);

                    Console.ReadLine();

                }

                else if (operation == "x"){

                    answer = numOne * numTwo;

                    Console.WriteLine(numOne + " x " + numTwo + " is " + answer);

                    Console.ReadLine();

                }

                else if (operation == "/"){

                    answer = numOne / numTwo;

                    Console.WriteLine(numOne + " / " + numTwo + " is " + answer);

                    Console.ReadLine();

                }

            else {

                Console.WriteLine ("ERROR");

            }

        }

}

​