Lekcja 2(working)

// ConsoleApplication3.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <math.h>

using namespace std;

double lagran(double *xa, double *ya, double poz);

const double FIRST = 0.3;
const double SECOND = 1.5;
const double THIRD = 2.8;
const int ARR_SIZE = 6;

int main()
{
    double y[] = { 0.100167, 0.636654, 1.50946, 2.94217, 6.69473, 10.0179 };
    double x[] = { 0.1, 0.6, 1.2, 1.8, 2.6, 3 };
    cout << "Wynik dla " << FIRST << " to: " << lagran(x, y, FIRST) << endl;
    cout << "Wynik dla " << SECOND << " to: " << lagran(x, y, SECOND) << endl;
    cout << "Wynik dla " << THIRD << " to: " << lagran(x, y, THIRD) << endl;

    cout << "Wynik dla sinh " << FIRST << " to: " << sinh(FIRST) << " roznica: "  << abs(lagran(x, y, FIRST) - sinh(FIRST)) << endl;
    cout << "Wynik dla sinh " << SECOND << " to: " << sinh(SECOND) << " roznica: " << abs(lagran(x, y, SECOND) - sinh(SECOND)) << endl;
    cout << "Wynik dla sinh " << THIRD << " to: " << sinh(THIRD) << " roznica: " << abs(lagran(x, y, THIRD) - sinh(THIRD)) << endl;
    system("PAUSE");
    return 0;
}

double lagran(double *xa, double *ya, double poz) {
    double wynik = 0.0;
    double tmp;

    for (int i(0); i < ARR_SIZE; i++) {
        tmp = 1.0;
        for (int j(0); j < ARR_SIZE; j++) {
            if (j != i) {
                tmp = tmp*((poz - xa[j]) / (xa[i] - xa[j]));
            }
        }
        wynik += tmp*ya[i];
    }

    return wynik;
}