Task: Cistercian numerals


C++: #include <array>
#include <iostream>

template<typename T, size_t S>
using FixedSquareGrid = std::array<std::array<T, S>, S>;

struct Cistercian {
public:
    Cistercian() {
        initN();
    }

    Cistercian(int v) {
        initN();
        draw(v);
    }

    Cistercian &operator=(int v) {
        initN();
        draw(v);
    }

    friend std::ostream &operator<<(std::ostream &, const Cistercian &);

private:
    FixedSquareGrid<char, 15> canvas;

    void initN() {
        for (auto &row : canvas) {
            row.fill(' ');
            row[5] = 'x';
        }
    }

    void horizontal(size_t c1, size_t c2, size_t r) {
        for (size_t c = c1; c <= c2; c++) {
            canvas[r][c] = 'x';
        }
    }

    void vertical(size_t r1, size_t r2, size_t c) {
        for (size_t r = r1; r <= r2; r++) {
            canvas[r][c] = 'x';
        }
    }

    void diagd(size_t c1, size_t c2, size_t r) {
        for (size_t c = c1; c <= c2; c++) {
            canvas[r + c - c1][c] = 'x';
        }
    }

    void diagu(size_t c1, size_t c2, size_t r) {
        for (size_t c = c1; c <= c2; c++) {
            canvas[r - c + c1][c] = 'x';
        }
    }

    void drawOnes(int v) {
        switch (v) {
        case 1:
            horizontal(6, 10, 0);
            break;
        case 2:
            horizontal(6, 10, 4);
            break;
        case 3:
            diagd(6, 10, 0);
            break;
        case 4:
            diagu(6, 10, 4);
            break;
        case 5:
            drawOnes(1);
            drawOnes(4);
            break;
        case 6:
            vertical(0, 4, 10);
            break;
        case 7:
            drawOnes(1);
            drawOnes(6);
            break;
        case 8:
            drawOnes(2);
            drawOnes(6);
            break;
        case 9:
            drawOnes(1);
            drawOnes(8);
            break;
        default:
            break;
        }
    }

    void drawTens(int v) {
        switch (v) {
        case 1:
            horizontal(0, 4, 0);
            break;
        case 2:
            horizontal(0, 4, 4);
            break;
        case 3:
            diagu(0, 4, 4);
            break;
        case 4:
            diagd(0, 4, 0);
            break;
        case 5:
            drawTens(1);
            drawTens(4);
            break;
        case 6:
            vertical(0, 4, 0);
            break;
        case 7:
            drawTens(1);
            drawTens(6);
            break;
        case 8:
            drawTens(2);
            drawTens(6);
            break;
        case 9:
            drawTens(1);
            drawTens(8);
            break;
        default:
            break;
        }
    }

    void drawHundreds(int hundreds) {
        switch (hundreds) {
        case 1:
            horizontal(6, 10, 14);
            break;
        case 2:
            horizontal(6, 10, 10);
            break;
        case 3:
            diagu(6, 10, 14);
            break;
        case 4:
            diagd(6, 10, 10);
            break;
        case 5:
            drawHundreds(1);
            drawHundreds(4);
            break;
        case 6:
            vertical(10, 14, 10);
            break;
        case 7:
            drawHundreds(1);
            drawHundreds(6);
            break;
        case 8:
            drawHundreds(2);
            drawHundreds(6);
            break;
        case 9:
            drawHundreds(1);
            drawHundreds(8);
            break;
        default:
            break;
        }
    }

    void drawThousands(int thousands) {
        switch (thousands) {
        case 1:
            horizontal(0, 4, 14);
            break;
        case 2:
            horizontal(0, 4, 10);
            break;
        case 3:
            diagd(0, 4, 10);
            break;
        case 4:
            diagu(0, 4, 14);
            break;
        case 5:
            drawThousands(1);
            drawThousands(4);
            break;
        case 6:
            vertical(10, 14, 0);
            break;
        case 7:
            drawThousands(1);
            drawThousands(6);
            break;
        case 8:
            drawThousands(2);
            drawThousands(6);
            break;
        case 9:
            drawThousands(1);
            drawThousands(8);
            break;
        default:
            break;
        }
    }

    void draw(int v) {
        int thousands = v / 1000;
        v %= 1000;

        int hundreds = v / 100;
        v %= 100;

        int tens = v / 10;
        int ones = v % 10;

        if (thousands > 0) {
            drawThousands(thousands);
        }
        if (hundreds > 0) {
            drawHundreds(hundreds);
        }
        if (tens > 0) {
            drawTens(tens);
        }
        if (ones > 0) {
            drawOnes(ones);
        }
    }
};

std::ostream &operator<<(std::ostream &os, const Cistercian &c) {
    for (auto &row : c.canvas) {
        for (auto cell : row) {
            os << cell;
        }
        os << '\n';
    }
    return os;
}

int main() {
    for (auto number : { 0, 1, 20, 300, 4000, 5555, 6789, 9999 }) {
        std::cout << number << ":\n";

        Cistercian c(number);
        std::cout << c << '\n';
    }

    return 0;
}