#include <iostream>
#include <iomanip>

using namespace std;

void wyswietlTablice(float **a, int n) {
    cout << setfill('-') << setw(16*n) << "" << endl;
    cout << setfill(' ');
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cout << "a[" << i << ", " << j << "]: " << setw(4) << a[i][j] << " | ";
        }
        cout << endl;
    }
    cout << setfill('-') << setw(16*n) << "" << endl;
    cout << setfill(' ');
}

void gauss(float **a, int n) {
    float p[n];

    for (int k = 0; k < n; k++) {
        cout << endl << "Krok " << k << endl;

        if (a[k][k] == 0) {
            cout << "Zero w elemencie [" << k << ", " << k << "]" << endl;
            return;
        }

        // Obliczanie P
        for (int i = k+1; i < n; i++) {
            p[i] = a[i][k] / a[k][k];
            cout << "P[" << i << "]: " << p[i] << endl;

            // Zmiana wiersza
            for (int j = 0; j < n; j++) {
                a[i][j] -= p[i] * a[0][j];
            }
        }

        wyswietlTablice(a, n);
    }
}

float** stworzTablice(int n) {
    float **a = new float*[n];
    for (int i = 0; i < n; i++) {
        a[i] = new float[n];
    }

    return a;
}

int main() {


    cout << "1. Wpolczynniki 1" << endl;
    cout << "2. Wpolczynniki 2" << endl;
    cout << "3. Wpolczynniki 3" << endl;
    cout << "4. Wpolczynniki wlasne" << endl;
    cout << "Wybor: ";
    int wybor;
    cin >> wybor;

    switch(wybor) {
    case 1: {
        // Demo wspolczynniki
        int n = 3;
        float **a = stworzTablice(n);
        a[0][0] = 1;
        a[0][1] = 2;
        a[0][2] = -1;
        a[1][0] = 2;
        a[1][1] = 1;
        a[1][2] = 0;
        a[2][0] = -1;
        a[2][1] = 1;
        a[2][2] = 2;
        wyswietlTablice(a, n);

        gauss(a, n);
        break;
    }
    case 2: {
        // Demo wspolczynniki
        int n = 4;
        float **a = stworzTablice(n);
        a[0][0] = 1;
        a[0][1] = 1;
        a[0][2] = -3;
        a[0][3] = 1;
        a[1][0] = 0;
        a[1][1] = 2;
        a[1][2] = -1;
        a[1][3] = 2;
        a[2][0] = 1.5;
        a[2][1] = 3.5;
        a[2][2] = -3.5;
        a[2][3] = 6.5;
        a[3][0] = 0.5;
        a[3][1] = 1.5;
        a[3][2] = 0;
        a[3][3] = 7.5;
        wyswietlTablice(a, n);

        gauss(a, n);
        break;
    }
    case 4:
        // Wlasne wspolczynniki
        int n;
        cout << "Podaj ilosc wspolczynnikow (n): ";
        cin >> n;

        float **a = stworzTablice(n);

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                a[i][j] = 0;
                cout << "a[" << i << ", " << j << "]: ";
                cin >> a[i][j];
            }
        }

        wyswietlTablice(a, n);

        gauss(a, n);
        break;
    }

    return 0;
}