Iterpolacja

#include <iostream>
#include <cmath>
#include <iomanip>
#include <fstream>
#include <cstdlib>
#include <ctime>
using namespace std;
void interpolacja(double x, int ilosc, double *tab, double *tab1)
{

	double *l = new double[ilosc];
	for (int i = 0; i < ilosc; i++)
	{
		if (i == ilosc-2)
		{
			l[i] = ((x - tab[i + 1]) / (tab[i] - tab[i + 1]))*((x - tab[0]) / (tab[i ] - tab[0]));
		}
		else if (i == ilosc - 1)
		{
			l[i] = ((x - tab[0]) / (tab[i] - tab[0]))*((x - tab[1]) / (tab[i] - tab[1]));
		}
		else
		{
			l[i] = ((x - tab[i + 1]) / (tab[i] - tab[i + 1]))*((x - tab[i + 2]) / (tab[i] - tab[i + 2]));
		}

	}
	double L = 0;
	for (int i = 0; i < ilosc; i++)
	{
		L = L + (tab1[i] * l[i]);
	}
	cout <<"L(x) = "<< L << endl;;
}
int main()
{
	cout << "Wprowadz dla jakiej wartosci znalezc interpolacje: ";
	double x;
	cin >> x;
	int ilosc = 3;
	double *tab = new double[ilosc];
	double *tab1 = new double[ilosc];
	tab[0] = 1;
	tab[1] = 3;
	tab[2] = 5;
	tab1[0] = 12;
	tab1[1] = 4;
	tab1[2] = 4;
	interpolacja(x, ilosc, tab, tab1);


	system("pause");
}