using System;
using System.Collections.Generic;

namespace calc.example
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                var x = Calculator.GetValue();

                Console.WriteLine();

                var operation = Calculator.GetOperation();

                Console.WriteLine();

                var y = Calculator.GetValue();

                Console.WriteLine();

                Console.WriteLine($"Result: {operation(x, y)}");

                Console.WriteLine("\n\nPress any key to continue...");
                Console.ReadLine();
                Console.Clear();
            }
        }
    }

    static class Calculator
    {
        public static double GetValue()
        {
            Console.Write("Number: ");

            var input = Console.ReadLine();
            if (double.TryParse(input, out double value))
                return value;

            Console.WriteLine("Incorrect Format");
            return GetValue();
        }

        private static Dictionary<char, Func<double, double, double>> operations = new Dictionary<char, Func<double, double, double>>()
        {
            { '+', (x, y) => x + y },
            { '-', (x, y) => x - y },
            { '*', (x, y) => x * y },
            { '/', (x, y) => x / y },
            { '%', (x, y) => x % y }
        };

        public static Func<double, double, double> GetOperation()
        {
            Console.Write("Operation: ");

            var input = Console.ReadLine();
            if (char.TryParse(input, out char character) && operations.TryGetValue(character, out Func<double, double, double> operation))
                return operation;

            Console.WriteLine("Incorrect Format");
            return GetOperation();
        }
    }
}