我在c++控制台中做了一个移动的屏幕保护程序，但当它到达角落时出现了一个bug

#include <iostream>
#include <conio.h> // for _getch()

const int WIDTH = 80;
const int HEIGHT = 24;

struct Position {
    int x, y;
};

void moveObject(Position &pos, char direction) {
    switch (direction) {
        case 'w': // Up
            if (pos.y > 0) pos.y--;
            else pos.y = HEIGHT - 1;
            break;
        case 's': // Down
            if (pos.y < HEIGHT - 1) pos.y++;
            else pos.y = 0;
            break;
        case 'a': // Left
            if (pos.x > 0) pos.x--;
            else pos.x = WIDTH - 1;
            break;
        case 'd': // Right
            if (pos.x < WIDTH - 1) pos.x++;
            else pos.x = 0;
            break;
    }
}

void drawObject(const Position &pos) {
    system("cls"); // Clear the console
    for (int y = 0; y < HEIGHT; ++y) {
        for (int x = 0; x < WIDTH; ++x) {
            if (x == pos.x && y == pos.y) {
                std::cout << "*";
            } else {
                std::cout << " ";
            }
        }
        std::cout << std::endl;
    }
}

int main() {
    Position pos = {WIDTH / 2, HEIGHT / 2};
    char input;

    while (true) {
        if (_kbhit()) { // Check if a key is pressed
            input = _getch();
            moveObject(pos, input);
        }
        drawObject(pos);
    }

    return 0;
}