квадратное_уравнение

#include <iostream>

using namespace std;

double solver_square(double arr[], double x[]);

void test_solver_square() {
    // a*x*x + b*x + c = 0
    double a = -1;
    double b = 3;
    double c = 4;

    double arr[]{a,b,c};
    double sol[2];

    double x;
    solver_square(arr, sol);

    x = sol[0];
    cout << x << " : " << a * x * x + b * x + c << endl;

    x = sol[1];
    cout << x << " : " << a * x * x + b * x + c << endl;

}

/// <summary>
/// Solve square equation
/// </summary>
/// <param name="arr">a, b, c</param>
/// <param name="x">solutions</param>
/// <returns></returns>
double solver_square(double arr[], double x[]) {
    double a = arr[0];
    double b = arr[1];
    double c = arr[2];

    double d = b * b - 4 * a * c;

    if (d >= 0) {
        x[0] = (-b - sqrt(d)) / (2 * a);
        x[1] = (-b + sqrt(d)) / (2 * a);
        return 0;
    }
    else
        return 1;
}

int counter = 0;

bool check_pin(int pin) {
    counter++;
    if (counter >= 3) {
        cout << "Unbloced pin" << endl;
        return false;
    }

    return pin == 1234;
}

void brutal_force() {
    srand(time(NULL));
    int pin;

    while (true) {
        pin = rand() % 10000;
        if (check_pin(pin)) {
            cout << "The safe is opened." << endl;
            cout << "Pin: " << pin << endl;
            cout << "Count: " << counter << endl;
            break;
        }
    }
}

const int n = 20;
char buff[n][n];

void clear_buff() {
    for (int y = 0; y < n; y++) {
        for (int x = 0; x < n; x++) {
            buff[x][y] = ' ';
        }
    }
}

void create_figure(int fig) {
    for (int y = 0; y < n; y++) {
        for (int x = 0; x < n; x++) {
            if ( -(y - n/2) == (x - n/2)  ||
                 (y - n / 2) == (x - n / 2))
                buff[x][y] = '@';
        }
    }
}

void show_figure() {
    for (int y = 0; y < n; y++) {
        for (int x = 0; x < n; x++) {
            cout << buff[x][y] << " ";
        }
        cout << endl;
    }
}

int main() {
    //test_solver_square();
    //brutal_force();
    clear_buff();
    create_figure(1);
    show_figure();


    return 0;
}