CSLight #9

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSLight
{
    class Program
    {
        static void Main(string[] args)
        {
            double usd = 15;
            double nzd = 23;
            double aud = 19;

            string exitCommand = "exit";
            string userInput;
            int choiceFrom;
            int choiceTo;
            double transfer;
            bool isProgramRunning = true;

            double usdToNzd = 1.4;
            double usdToAud = 1.2;
            double nzdToUsd = 5.0 / 7.0;
            double nzdToAud = 6.0 / 7.0;
            double audToUsd = 5.0 / 6.0;
            double audToNzd = 1.1;

            while (isProgramRunning)
            {
                Console.WriteLine($"\nБаланс:\nUSD - {usd}\nNZD - {nzd}\nAUD - {aud}\n");
                Console.WriteLine("Из какой валюты конвертируем?\n1) USD\n2) NZD\n3) AUD\nexit - Выход из конвертера\n");
                userInput = Console.ReadLine();

                if (userInput.ToLower() == exitCommand)
                {
                    isProgramRunning = false;
                    continue;
                }
                else
                {
                    choiceFrom = Convert.ToInt32(userInput);
                }

                Console.WriteLine("\nВ какую валюту конвертируем?\n1) USD\n2) NZD\n3) AUD\nexit - Выход из конвертера\n");
                userInput = Console.ReadLine();

                if (userInput.ToLower() == exitCommand)
                {
                    isProgramRunning = false;
                    continue;
                }
                else
                {
                    choiceTo = Convert.ToInt32(userInput);
                }

                Console.WriteLine("\nСумма перевода:");
                transfer = Convert.ToSingle(Console.ReadLine());

                if (choiceFrom == 1 && choiceTo == 2)
                {
                    if (transfer <= usd)
                    {
                        nzd += transfer * usdToNzd;
                        usd -= transfer;
                    }
                    else
                    {
                        Console.Clear();
                        Console.WriteLine("Сделка невозможна.Повторите Ввод:");
                    }
                }

                if (choiceFrom == 1 && choiceTo == 3)
                {
                    if (transfer <= usd)
                    {
                        aud += transfer * usdToAud;
                        usd -= transfer;
                    }
                    else
                    {
                        Console.Clear();
                        Console.WriteLine("Сделка невозможна.Повторите Ввод:");
                    }
                }

                if (choiceFrom == 2 && choiceTo == 1)
                {
                    if (transfer <= nzd)
                    {
                        usd += transfer * nzdToUsd;
                        nzd -= transfer;
                    }
                    else
                    {
                        Console.Clear();
                        Console.WriteLine("Сделка невозможна.Повторите Ввод:");
                    }
                }

                if (choiceFrom == 2 && choiceTo == 3)
                {
                    if (transfer <= nzd)
                    {
                        aud += transfer * nzdToAud;
                        nzd -= transfer;
                    }
                    else
                    {
                        Console.Clear();
                        Console.WriteLine("Сделка невозможна.Повторите Ввод:");
                    }
                }

                if (choiceFrom == 3 && choiceTo == 1)
                {
                    if (transfer <= aud)
                    {
                        usd += transfer * audToUsd;
                        aud -= transfer;
                    }
                    else
                    {
                        Console.Clear();
                        Console.WriteLine("Сделка невозможна.Повторите Ввод:");
                    }
                }

                if (choiceFrom == 3 && choiceTo == 2)
                {
                    if (transfer <= aud)
                    {
                        nzd += transfer * audToNzd;
                        aud -= transfer;
                    }
                    else
                    {
                        Console.Clear();
                        Console.WriteLine("Сделка невозможна.Повторите Ввод:");
                    }
                }
            }
        }
    }
}