Snake game in C++

Some time ago friend asked to help his kid with C++ task - to write a snake game in console app.
One day after here it is - the fruit of my rusty C++ skills:

Code:

#include <iostream>
#include <conio.h>
#include <sys/timeb.h>
#include <time.h>
#include <deque>

using namespace std;

const int WIDTH = 40;
const int HEIGHT = 20;
const time_t TICK_MS = 500;


enum class Action { Stop, Continue, Up, Down, Left, Right };

static time_t GetCurrentTimeMS() {
    _timeb current_time = { 0 };
    _ftime_s(&current_time);
    return current_time.time * 1000 + current_time.millitm;
}


class Field {
public:
    Field() {
        for (int y = 0; y < HEIGHT; y++) {
            bool isFirstRow = (y == 0);
            bool isLastRow = (y == (HEIGHT - 1));
            for (int x = 0; x < WIDTH; x++) {
                bool isFisrtColumn = (x == 0);
                bool isLastColumn = (x == (WIDTH - 1));
                if (isFirstRow || isLastRow) chars[y][x] = '-';
                else if (isFisrtColumn || isLastColumn) chars[y][x] = '|';
                else chars[y][x] = ' ';
            }
        }
        fruit = NULL;
        zmeika = NULL;
    }

    ~Field() {
        if (fruit != NULL) {
            delete fruit; fruit = NULL;
        }
        if (zmeika != NULL) {
            delete zmeika; zmeika = NULL;
        }
    }

    void Draw() {
        system("cls");
        for (int y = 0; y < HEIGHT; y++)
        {
            cout.write(chars[y], WIDTH) << endl;
        }
        cout << "Fruits: " << GetScore();
    }

    void AddZmeikaAndFruit() {
        if (zmeika == NULL) {
            AddZmeika();
        }
        if (fruit == NULL) {
            AddFruit();
        }
    }

    bool PerformZmeikaAction(Action zmeikaAction) {
        if (zmeikaAction == Action::Stop)
            return true;

        bool success_move = zmeika->MoveHead(zmeikaAction);
        BodyCell head = zmeika->GetHead();

        if (success_move == false) {
            chars[head.Y][head.X] = 'X';
            return true;
        }

        if (head.Y == fruit->Y && head.X == fruit->X) {
            zmeika->EatFruit();
            AddFruit();
        }
        else {
            BodyCell tail = zmeika->CutTail();
            chars[tail.Y][tail.X] = ' ';
            if (IsBorder(head.Y, head.X)) {
                chars[head.Y][head.X] = 'X';
                return true;
            }
        }

        chars[head.Y][head.X] = head.Symbol;
        return false;
    }

    int GetScore() {
        if (zmeika == NULL) {
            return 0;
        }
        return zmeika->EatenFruits();
    }


private:

    void AddZmeika() {
        zmeika = new Zmeika(HEIGHT/2, WIDTH/2);
        BodyCell head = zmeika->GetHead();
        chars[head.Y][head.X] = head.Symbol;
    }

    void AddFruit() {
        if (fruit != NULL) {
            delete fruit; fruit = NULL;
        }
        int fy, fx;
        do {
            fx = rand() % WIDTH; fy = rand() % HEIGHT;
        } while (IsBorder(fy, fx) || zmeika->IsBody(fy, fx));
        fruit = new Fruit(fy, fx);
        chars[fruit->Y][fruit->X] = fruit->Symbol;
    }

    bool IsBorder(int y, int x) {
        return (y == 0) || (y == HEIGHT - 1) || (x == 0) || (x == WIDTH - 1);
    }

    struct BodyCell {
        int Y;
        int X;
        char Symbol;

        BodyCell(int y, int x) {
            Y = y; X = x; Symbol = '@';
        }
    };

    class Zmeika {
    public:
        Zmeika(int y, int x) {
            currentAction = Action::Down;
            BodyCell head(y, x);
            body.push_front(head);
            fruits = 0;
        }

        bool IsBody(int y, int x) {
            for(BodyCell cell : body) {
                if ((cell.Y == y) && (cell.X == x))
                    return true;
            }
            return false;
        }
    
        BodyCell GetHead() {
            return body.front();
        }

        BodyCell CutTail() {
            BodyCell tail = body.back();
            body.pop_back();
            return tail;
        }

        bool MoveHead(Action action) {
            BodyCell head = body.front();
            if (action == Action::Continue)
                action = currentAction;
            else
                currentAction = action;
            BodyCell new_head(head.Y, head.X);
            switch (action)
            {
            case Action::Down: new_head.Y += 1; break;
            case Action::Up: new_head.Y -= 1; break;
            case Action::Right: new_head.X += 1; break;
            case Action::Left: new_head.X -= 1; break;
            }
            if (IsBody(new_head.Y, new_head.X))
                return false;
            body.push_front(new_head);
            return true;
        }

        void EatFruit() {
            fruits++;
        }

        int EatenFruits() {
            return fruits;
        }

    private:

        deque<BodyCell> body;
        Action currentAction;
        int fruits;
    };

    class Fruit {
    public:
        int Y;
        int X;
        char Symbol;

        Fruit(int y, int x) {
            Y = y; X = x; Symbol = '*';
        }
    };

    char chars[HEIGHT][WIDTH] = { 0 };
    Zmeika* zmeika;
    Fruit* fruit;
};

static Action GetActionFromUser(time_t milliseconds_to_wait) {
    time_t start_milliseconds = GetCurrentTimeMS();

    do {
        while (0 == _kbhit()) {
            time_t elapsed_milliseconds = GetCurrentTimeMS() - start_milliseconds;
            if (elapsed_milliseconds >= milliseconds_to_wait)
                return Action::Continue;
        }
        switch (_getch()) {
            case 13: 
                return Action::Stop;
            case 0:
            case 0xE0:
                switch(_getch()) {
                    case 75:
                        return Action::Left;
                    case 77:
                        return Action::Right;
                    case 72:
                        return Action::Up;
                    case 80:
                        return Action::Down;
            }
        }
    } while (true);
}


int main()
{
    Field field;
    field.AddZmeikaAndFruit();
    field.Draw();

    bool gameOver = false;
    while(gameOver == false) {
        Action action = GetActionFromUser(TICK_MS);
        gameOver = field.PerformZmeikaAction(action);
        field.Draw();
    }
    cout << endl << "Game over!" << endl;
}

Comments were in Russian, being too lazy I just removed them instead of translating...