aan_11

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

using namespace std;


void wyswietlMacierz(double l[3][3])
{
    for (int j = 0 ; j < 3 ; j ++)
    {
        cout << "| ";
        for (int i = 0 ; i < 3 ; i ++) cout << l[j][i] << " ";
        cout << "|" << endl;
    }
}


void stworzMacierz(int n, double a[3][3], double l[3][3])
{
    double suma;

    for (int s = 0 ; s < n ; s ++)
    {
        for (int j = s ; j < n ; j ++)
        {
            suma = 0;
            for (int i = 0 ; i < s ; i ++) suma += l[j][i] * l[s][i];
            l[j][s] = a[j][s] - suma;

            if (s == j) l[j][s] = sqrt (l[j][s]);
            else l[j][s] /= l[s][s];
        }
    }

    wyswietlMacierz(l);
}


int main ()
{
    double a[3][3] = {{1, 2, 3}, {2, 8, 10}, {3, 10, 22}};
    double b[3] = {1, 3, 7};
    double l[3][3] = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
    double x[3];
    double y[3];
    int n = 3;
    float s = 0;
    double t;

    cout << "Stworzenie macierzy L" << endl;
    stworzMacierz(n, a, l);

    cout << endl << "Obliczanie wektora y" << endl;
    y[0] = l[0][0];

    for (int i = 1 ; i < n ; i ++)
    {
        s = 0;
        for (int j = 0 ; j < i ; j ++) s = s + l[i][j] * y[j];
        y[i] = (b[i] - s) / l[i][i];
    }

    for (int i = 0 ; i < 3 ; i ++) cout << "y[" << i << "] = " << y[i] << endl;

    cout << endl << "Transpozycja macierzy L" << endl;

    for (int j = 0 ; j < n - 1 ; j++)
    {
        for (int i = j + 1 ; i < n ; i ++)
        {
            t = l[j][i];
            l[j][i] = l[i][j];
            l[i][j] = t;
        }
    }

    wyswietlMacierz(l);

    cout << endl << "Obliczanie wektora x" << endl;

    x[2] = y[2] / l[2][2];
    x[1] = (y[1] - (l[1][2] * x[2])) / l[1][1];
    x[0] = (y[0] - ((l[0][1] * x[1]) + l[0][2] * x[2])) / l[0][0];

    for (int i = 0 ; i < 3 ; i ++) cout << "x[" << i << "] = " << x[i] << endl;
}