using System;

public class Program

{

    public static void Main()

    {

            Kalkulacka calc = new Kalkulacka();

            Reading enter = new Reading();

​

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            enter.input = null;

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            while (enter.input != "Exit")

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            {

                Console.Write("Zadej první číslo (pokud zadáš X, tak se kalkulačka ukončí): ");

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                enter.ReadInput();

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                if (enter.input == "Exit")

                {

                    return;

                }

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                else

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                    enter.ReadNumber();

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                calc.FstNumber = enter.Number;

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                calc.ContSign = false;

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                enter.ReadSign();

                calc.Sign = enter.input;

                calc.SignOK();

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                if (calc.ContSign && calc.Sign != "^")

                {

                    Console.Write("Zadej druhé číslo: ");

                    enter.ReadInput();

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                    enter.ReadNumber();

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                    if (enter.Number == 0 && calc.Sign == "/")

                        while (enter.Number == 0)

                        {

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                            if (enter.Number == 0)

                            {

                                Console.Write("Dělení nulou není definováno! Zadej druhé číslo znovu: ");

                            }

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                            enter.ReadInput();

                            enter.ReadNumber();

                        }

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                    calc.ScdNumber = enter.Number;

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                    calc.Calculation(calc.FstNumber, calc.Sign, calc.ScdNumber);

                }

                else

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                     if (calc.ContSign && calc.Sign == "^")

                {

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                    enter.ReadNumberPow();

                    calc.ScdNumber = enter.Number;

                    calc.Calculation(calc.FstNumber, calc.Sign, calc.ScdNumber);

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                }

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                Console.WriteLine("Výsledek: " + calc.FstNumber + calc.Sign + calc.ScdNumber + "=" + calc.Result);

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            }

    }

}

​

    class Reading

    {

        public string input = null;

        public bool Exit = false;

        public bool OK;

        public double Number;

        public int ScdNumberPow;

        public bool OKS = false;

        public void TypeAgain()

        {

            Console.Write("Není číslo, zadej znovu: ");

        }

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        public double ReadNumber()

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        {

            OK = double.TryParse(input, out Number);

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            if (!OK)

            {

                while (!OK)

                {

                    TypeAgain();

                    ReadInput();

                    OK = double.TryParse(input, out Number);

                }

            }

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            return Number;

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        }

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        public double ReadNumberPow()

​

        {

            Console.Write("Zadej druhé celé číslo, program umí mocnit pouze celými čísly: ");

            OK = int.TryParse(Console.ReadLine(), out ScdNumberPow);

            if (!OK)

            {

            while (!OK)

                {

                    Console.Write("Není celé číslo, zadej znovu: ");

                    OK = int.TryParse(Console.ReadLine(), out ScdNumberPow);

                }

            }

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            Number = (double)ScdNumberPow;

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            return Number;

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        }

​

​

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        public string ReadInput()

        {

            input = Console.ReadLine();

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            if (input == "X")

            {

                input = "Exit";

                return input;

            }

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            else

                return input;

        }

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        public string ReadSign()

        {

            Console.Write("Zadej operátor (+,-,*,/,^): ");

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            while (!OKS)

            {

                input = Console.ReadLine();

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                if (input == "*" || input == "+" || input == "-" || input == "/" || input == "^")

                {

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                    return input;

                }

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                else

                    Console.Write("Není platný operátor, zadej znovu: ");

                    OKS = false;

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            }

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            return input;

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        }

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    }

​

    class Kalkulacka

    {

        public string Sign;

        public double FstNumber;

        public double ScdNumber;

        public double Result;

        public bool ContSign;

        public bool SignOK()

        {

            if (Sign == "*" || Sign == "+" || Sign == "-" || Sign == "/" || Sign == "^")

            {

                ContSign = true;

            }

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            else

                ContSign = false;

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            return ContSign;

        }

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        public double Count(double a, double b)

        {

            Result = a + b;

            return Result;

        }

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        public double Minus(double a, double b)

        {

            Result = a - b;

            return Result;

        }

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        public double Times(double a, double b)

        {

            Result = a * b;

            return Result;

        }

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        public double Divided(double a, double b)

        {

            Result = a / b;

            return Result;

        }

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        public double Pow(double a, double b)

        {

            Result = 1;

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            if (b > 0)

            {

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                for (double i = 0; i < b; i++)

                    Result = a * Result;

            }

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            else

                if (b < 0 && b > -2)

            {

                for (double i = 0; i < (b * -1); i++)

                    Result = (1 / a) * (1 / Result);

            }

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            else

                if (b < -2)

            {

                Result = (1 / a) * (1 / a);

                for (double i = 1; i < ((b * -1) - 1); i++)

                    Result = (1 / a) * Result;

            }

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            else

                if (b == -2)

            {

                for (double i = 0; i < (b * -1); i++)

                    Result = (1 / a) * (1 / a);

            }

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            return Result;

        }

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        public double Calculation (double c, string s, double d)

        {

            if (s == "+")

            {

                Count(c, d);

            }

            else

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              if (s == "-")

            {

                Minus(c, d);

            }

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            else

               if (s == "*")

            {

                Times(c,d);

            }

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            else

              if (s == "/")

            {

               Divided(c, d);

            }

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            else 

                if (s =="^")

            {

                Pow(c, d);

            }

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            return Result;

        }

    }