有大神帮注释一下吗，谢谢
#include <iostream>
#include <vector>
#include <ctime>
#include <cstdlib>
#include <conio.h>
#include <windows.h>
using namespace std;
enum Direction {UP, DOWN, LEFT, RIGHT};
//Frame of the game
class Frame {
public:
friend class snakeNode;
friend class movement;
unsigned width, height;
Frame(): width(30), height(30) {}
void setHeight(unsigned hgt) {
height = hgt;
}
void setWidth(unsigned wid) {
width = wid;
}
void initializeFrame();
void displayFrame();
private:
vector< vector<char> > window;
}frame;
void Frame::initializeFrame() {
if (width <= 0 || height <= 0) {
cerr << "WRONG FRAME DIMENSION!" << endl;
exit(0);
}
window = vector<vector<char> >(height, vector<char>(width, ' '));
for (int i = 0; i != height; ++i) {
window[i][0] = window[i][width-1] = '#';
}
for (int j = 0; j != width; ++j) {
window[0][j] = window[height-1][j] = '#';
}
}
void Frame::displayFrame() {
for (int i = 0; i != height; ++i) {
for (char ch : window[i])
cout << ch << ' ';
cout << endl;
}
}
//snakeNode
class snakeNode {
public:
friend class movement;
snakeNode(int ix, int iy): x(ix), y(iy), next(nullptr), prior(nullptr) {}
void addHead(int, int);
void delTail();
private:
int x, y;
snakeNode *next, *prior;
}*head, *tail;
void snakeNode::addHead(int ix, int iy) {
snakeNode *newSnake = new snakeNode(ix, iy);
newSnake->next = head;
if (head)
head->prior = newSnake;
else
tail = newSnake;
head = newSnake;
frame.window[ix][iy] = '~';
}
void snakeNode::delTail() {
snakeNode *snakeTail = tail;
frame.window[snakeTail->x][snakeTail->y] = ' ';
tail = snakeTail->prior;
if (tail)
tail->next = nullptr;
else
head = nullptr;
delete snakeTail;
}
//movement
class movement {
public:
movement(): dir(LEFT) {randomFood();}
void randomFood();
void move();
void changeDirection(char);
private:
enum Direction dir;
int fx, fy;
bool outOfFrame(int h, int w) {
return h < frame.height - 1 && h > 0 && w < frame.width - 1 && w > 0 ? false : true;
}
bool block(int h, int w) {
for (snakeNode *snake = head; snake; snake = snake->next) {
if (snake->x == h && snake->y == w)
return true;
}
return false;
}
};
void movement::randomFood() {
srand((unsigned)time(0));
bool onSnake = true;
while (onSnake) {
onSnake = false;
fx = rand() % (frame.height - 2) + 1;
fy = rand() % (frame.width - 2) + 1;
for (snakeNode *snake = head; snake; snake = snake->next) {
if (fx == snake->x && fy == snake->y) {
onSnake = true; break;
}
}
}
frame.window[fx][fy] = 'x';
}
void movement::move() {
int h = head->x, w = head->y;
switch(dir) {
case UP: --h; break;
case DOWN: ++h; break;
case LEFT: --w; break;
case RIGHT: ++w; break;
}
if (outOfFrame(h, w) || block(h, w)) {
cout << "Game Over!" << endl;
exit(0);
}
if (h == fx && w == fy) {
head->addHead(fx, fy);
randomFood();
}
else {
head->addHead(h, w);
head->delTail();
}
}
void movement::changeDirection(char key) {
switch(key) {
case 'w': {
if (dir != DOWN) dir = UP;
break;
}
case 's': {
if (dir != UP) dir = DOWN;
break;
}
case 'a': {
if (dir != RIGHT) dir = LEFT;
break;
}
case 'd': {
if (dir != LEFT) dir = RIGHT;
break;
}
}
}
int main() {
unsigned speed, h, w;
char key;
cout << "Please input height and width!(10~39)" << endl;
cout << "height = ";
cin >> h;
cout << "width = ";
cin >> w;
cout << "Please input speed!(1~500)" <<endl;
cout << "speed = ";
cin >> speed;
frame.setHeight(h); frame.setWidth(w);
frame.initializeFrame();
head->addHead(frame.height / 2, frame.width / 2);
movement myMove;
while (true) {
while (!kbhit()) {
system("cls");
myMove.move();
frame.displayFrame();
Sleep(speed);
}
key = getch();
myMove.changeDirection(key);
}
return 0;
}
