using System;

public class Program

{

     double x0 = 0, x1 = 0, x2 = 0, x3 = 0, xN;

     double y0 = 0, y1 = 0, y2 = 0, y3 = 0, yN;

    public void Main()

    {

        Console.WriteLine("PERHITUNGAN INTERPOLASI LINEAR\n");  

        Console.WriteLine("Masukkan x0");  

        double x0 = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Masukkan x1"); 

        double x1 = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Masukkan x2"); 

        double x2 = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Masukkan x3"); 

        double x3 = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Masukkan x"); 

        double xN = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Hasil Perhitungan adalah : ");

        CariYLain(x0, x1, x2, x3);

        double f = fungsi(xN);

        string hasil = string.Format("{0:0.00}", f);

        Console.WriteLine("Y(True) = {0}", hasil);

        double yN = interpolasiLinear(xN);

        hasil = string.Format("{0:0.00}", yN);

        Console.WriteLine("Y(Est) = {0}", hasil);

    }

    public double fungsi(double x)

    {

        double y = x*x - 2;

        return y;

    }

    public void hitungY()

    {

        y0 = fungsi(x0);

        y1 = fungsi(x1);

        if(x2 != 0) y2 = fungsi(x2);

        if(x3 != 0) y3 = fungsi(x3);

    }

    public double interpolasiLinear(double x)

    {

        hitungY();

        double y = (y1 - y0) / (x1 - x0) * (x - x0) + y0;

        return y;

    }

    public void CariYLain(double x0, double x1, double x2, double x3)

    {

        double nilai = fungsi(x0);

            string hasil = string.Format("{0:0.00}", nilai);

            Console.WriteLine("y0 = {0}", hasil);

            nilai = fungsi(x1);

            hasil = string.Format("{0:0.00}", nilai);

            Console.WriteLine("y1 = {0}", hasil);

            if (x2 != 0)

            {

                nilai = fungsi(x2);

                hasil = string.Format("{0:0.00}", nilai);

                Console.WriteLine("y2 = {0}", hasil);

            }

            if (x3 != 0)

            {

                nilai = fungsi(x3);

                hasil = string.Format("{0:0.00}", nilai);

                Console.WriteLine("y3 = {0}", hasil);

            }

    }

​

}