using System;

public class Program

{

    public static void Main()

    {

        const int installmentsAmount = 238;

        const int firstInstallmentNumber = 40;

        const double debt = 184764.78;

        // Console.WriteLine("Podaj numer raty:");

        //var input = Console.ReadLine();

        var input = "198";

        int installmentNumber = firstInstallmentNumber + int.Parse(input);

        if(installmentNumber < firstInstallmentNumber || installmentNumber > installmentsAmount)

            throw new ArgumentException($"Invalid installment number {installmentNumber}");

        double debtClone = debt;

        Installment installment = null;

        double intetestSum = 0;

        //Console.WriteLine($"initial debtClone: {debtClone}");

        for(var i = firstInstallmentNumber; i <= installmentNumber; i++)

        {

            installment = new(debtClone);

            intetestSum += installment.Interest;

            //installment.Fund += 1000.0;

            Console.WriteLine($"rata nr: {i}: {installment.ToString()}");

            debtClone = debtClone - installment.Fund;

            Console.WriteLine($"new debt: {debtClone.Round()}");

        }

        Console.WriteLine($"Spłacony kapitał: {(debt-debtClone).Round()}, suma zapłaconych odsetek: {intetestSum.Round()}");

        // Console.WriteLine($"Rata nr. {installmentNumber}: {installment.ToString()} (do spłaty: {debtClone.Round()})");

    }

    public record Installment

    {

        const double INSTALLMENT = 1688.65;

        const double FACTOR = 0.68;

        public Installment(double debt)

        {

            Interest = Math.Round((debt * FACTOR / 100), 4);

            Fund = Math.Round((INSTALLMENT - Interest), 4);

        }

        public double Fund { get; set; }

        public double Interest { get; }

        public override string ToString()

            => $"{nameof(Fund)}:{Fund}; {nameof(Interest)}:{Interest}";

    }

}

​

public static class Extensions

{

    public static double Round(this double d)

        => Math.Round(d, 4);

}