#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
int n = 5; // liczba elementow
double A[5][5]; /* zestaw 3= {10,1,1,1,2,10,1,4,2,1,5,1,2,9,5,3,0,1,10,1,6,2,1,1,20};*/ /* zestaw 1= { 10, 1, 1, 1, 2, 3, 20, 4, 2, 1, 5, 1, 40, 9, 5, 3, 0, 1, 10, 1, 6, 2, 1, 1, 20 };*/
double U[5][5];
double L[5][5];
double B[5]; /*z3= {15,18,22,15,30};*/ /*z1= { 15, 30, 60, 15, 30 };*/
double Y[5];
double X[5];

void zad3()
{
    Y[0] = B[0];
    double temp;
    for (int i = 1; i < n; i++)
    {
        temp = 0;
        for (int k = 0; k <= i - 1; k++)
        {
            temp += L[i][k] * Y[k];
        }
        Y[i] = B[i] - temp;
    }
    if (U[n - 1][n - 1] == 0)
        return;
    X[n - 1] = Y[n - 1] / U[n - 1][n - 1];
    double temp2;
    for (int i = n - 2; i >= 0; i--)
    {
        temp2 = 0;
        for (int k = i + 1; k <= n; k++)
        {
            temp2 += U[i][k] * X[k];
        }
        X[i] = (Y[i] - temp2) / U[i][i];
    }
}
void zad2()
{
    for (int i = 0; i < n; i++)     // zerowanie macierzy L i U
    {
        for (int j = 0; j < n; j++)
        {
            L[i][j] = 0;
            U[i][j] = 0;
        }
    }
    for (int i = 0; i < n; i++)     // ustawienie przekatnej L na wartosc 1
    {
        L[i][i] = 1;
    }
    int i = 0;
    int j = 0;
    int k = 0;
    for (j = 0; j < n; j++)
    {
        U[i][j] = A[i][j];
    }
    if (U[0][0] == 0)
    {
        std::cout << "nie moze byc xd";
        return;
    }
    for (j = 1; j < n; j++)
    {
        L[j][0] = A[j][0] / U[0][0];
    }
    j = 0;
    double temp = 0;
    for (i = 1; i < n; i++)
    {
        // liczenie U
        for (j = i; j < n; j++)
        {
            temp = 0;
            for (k = 0; k <= i - 1; k++)
            {
                temp += (L[i][k] * U[k][j]);
            }
            U[i][j] = A[i][j] - temp;
        }
        // liczenie L
        for (int j = i + 1; j < n; j++)
        {
            temp = 0;
            for (int k = 0; k <= i - 1; k++)
            {
                temp += L[j][k] * U[k][i];
            }
            if (U[i][i] == 0) return;
            L[j][i] = (A[j][i] - temp) / U[i][i];

        }
    }


    return;
}
void zad1() // dane do pliku podajemy: kazda liczba w osobnej linice, wierszami od lewej do prawej, bardzo wazne aby podac prawidlowy rozmiar. Najpierw macierz A potem wektor B
{
    std::ifstream file;
    file.open("test2.txt");
    if (file.is_open())
    {
        std::cout << "podaj rozmiar: ";
        std::cin >> n;
        for (int i = 0;i < n;i++)
        {
            for (int j = 0;j < n;j++)
            {
                file >> A[i][j];
            }
        }

        for (int i = 0;i < n;i++)
        {
            file >> B[i];
        }

        file.close();
        return;
    }

    else std::cout << "Couldn't open the file";
    return;

}
void zad4()
{
    std::ofstream file;
    file.open("raport.txt");
    if (file.is_open())
    {
        // dane wejsciowe

        file << "Dane wejsciowe\nMacierz A:\n";
        for (int i = 0; i < n; i++) // macierz A
        {
            for (int j = 0; j < n; j++)
            {
                file << A[i][j] <<"  ";
            }
            file << "\n";
        }
        file << "\n";
        file << "Wektor B:\n";

        for (int i = 0; i < n; i++) // wektor B
        {
                file << B[i]<< "  ";
        }
        file << "\n\n";

        // dane posrednie

        file << "Dane posrednie\nMacierz U:\n";
        for (int i = 0; i < n; i++)         // macierz U
        {
            for (int j = 0; j < n; j++)
            {
                file << U[i][j] << "  ";
            }
            file << "\n";
        }
        file << "\n";
        file << "Macierz L:\n";
        for (int i = 0; i < n; i++)         // macierz L
        {
            for (int j = 0; j < n; j++)
            {
                file << L[i][j] << "  ";
            }
            file << "\n";
        }
        // wyniki obliczen Wektory Y i X
        file << "\n";
        file << "wektor X:\n";
        //for (int i = 0;i < n;i++) // wektor X
        //{
        //  file << X[i] << " ";
        //}
        //file << "\n";
        //for (int i = 0;i < n;i++) // wektor X
        //{
        //  file << std::scientific<< X[i] << " ";
        //}
        //file << "\n";
        for (int i = 0;i < n;i++) // wektor X
        {
            file << std::scientific << std::setprecision(10) << X[i] << " ";
        }
        file << "\n";
        file << "\n";
        file << "wektor Y:\n";
        for (int i = 0;i < n;i++) // wektor Y
        {
            file << std::scientific << std::setprecision(10) << Y[i] << " ";
        }
        file << "\n";
        file.close();
        return;
    }

    return;
}
// funckje pomocnicze do testowania
void outputL()
{
    int i = 0, j = 0;
    for (i = 0; i < n; i++)
    {
        for (j = 0; j < n; j++)
        {
            printf("%f ", L[i][j]);
        }
        std::cout << "\n";
    }
}
void outputU()
{
    int i = 0, j = 0;
    for (i = 0; i < n; i++)
    {
        for (j = 0; j < n; j++)
        {
            printf("%f ", U[i][j]);
        }
        std::cout << "\n";
    }
}
void output2()
{
    int i = 0;;
    for (i = 0; i < n; i++)
    {
        std::cout << X[i] << std::endl;

    }
}
int main()
{
    zad1();
    zad2();
    zad3();
    zad4();
    system("pause");
    return 0;
}