#include "funcs.h"
#include <bits/stdc++.h>
#include <math.h>
#include <stdio.h>
using namespace std;


double skpr(double m[], double p[], int n){
    double sum = 0;
    for (int i = 0; i < n; i++) sum += m[i] * p[i];
    return sum;
}
void mult(double **A, double *b, double *c, int size){
    for (int i = 0; i < size; i++) {
        c[i] = skpr(A[i], b, size);
    }
}

void sol(double **A, double *x, double *b, int n){
    int j=0; //счетчик шагов
    double err; //погрешность
    cout << "Start Gauss " << endl;
    double **AA = array_generator(n,n);
    for (int j=0; j < n; j++) for (int i=0; i < n; i++) AA[j][i]=A[j][i]; //дубликат таблицы
    double *bb = array_generator(n);
    for (int j=0; j < n; j++) bb[j]=b[j]; //дубликат таблицы
    double kf = 0;
    for (int j = 0; j < n - 1; j++){
        for (int i = j + 1; i < n; i++){
            kf = A[i][j] / A[j][j];
            for (int k = j; k < n; k++) {
                A[i][k] -= A[j][k] * kf;
            }
            b[i] -= b[j] * kf;
        }
        if (n<10){
            cout << "Step: " << j+1 << endl;
            vivod(A,x,b,n,1);
            cout << endl;
        }
    }
    double sum = 0;
    for (int i = n - 1; i >= 0; i--){
        sum = 0;
        for (j = i + 1; j < n; j++)	{
            sum += A[i][j] * x[j];
        }
        x[i] = (b[i] - sum) / A[i][i];
    }

    //    cout << "Step: " << j << endl; //шаги
    //    vivod(A,b,x,n,1);
    //    cout << endl;
    cout << "Result:" <<endl;
    vivod(AA,bb,x,n,0);

    err = check(A,b,x,n); //считаем погрешность
    printf_s("Err: %14e", err);
    cout << endl;
    array_destroyer(AA,n);
}

double check(double **A, double *b, double *x, int size){
    double *err;
    err = new double[size];
    mult(A, x, err, size);
    for (int i = 0; i < size; i++){
        err[i] -= b[i];
    }
    double maxerr = 0;
    for (int i = 0; i < size; i++){
        if (maxerr < fabs(err[i])) maxerr = fabs(err[i]);
    }
    delete[]err;
    return maxerr;
}

void vivod(double **A, double *b, double *x, int n, int c){ //Вывод матрицы (c-вывод Х или значения х)
    for (int j=0; j < n; j++){
        for (int i=0; i < n; i++){
            if (c==1) cout << setw(7)  << fixed << setprecision(2)
                           << A[j][i] << " * x"   << ((i==n-1)?"":" + "); //магия таблицы
            else cout << setw(7)<< fixed << setprecision(2)  << A[j][i] << " * " << setw(7)
                      << fixed << setprecision(2) << x[i] << ((i==n-1)?"":" + "); //тоже магия таблицы
        }
        cout << " = " << b[j] << endl;
    }
}

int read_n(){
    int n;
    cout << "Please write size array:" << endl;
    cin >> n;
    return n;
}

double **array_generator_rand(int n, int m) {
    double **ptrary = new double * [n];
    srand(time(NULL));
    for (int i = 0; i < n; i++) {
        ptrary[i] = new double [m];
        for (int j=0; j < m; j++) ptrary[i][j]= rand() % 100;
    }
    return ptrary;
}

double **array_generator(int n, int m) {
    double **ptrary = new double * [n];
    for (int i = 0; i < n; i++) {
        ptrary[i] = new double [m];
    }
    return ptrary;
}

double *array_generator_rand(int n) {
    double *ptrary = new double [n];
    srand(time(NULL));
    for (int i=0; i < n; i++) ptrary[i] = rand() % 100;
    return ptrary;
}

double *array_generator(int n) {
    double *ptrary = new double [n];
    return ptrary;
}

void array_destroyer(double **ary, int n) {
    for (int i = 0; i < n; i++) {
        delete [] ary[i];
    }
    delete [] ary;
}

void array_destroyer(double *ary) {
    delete [] ary;
}