字符版本贪吃蛇游戏
这篇博客介绍了我是怎样通过自顶而下的方法一步步开发出一个字符版本的贪吃蛇游戏，并利用此前实现的智能蛇开发出全新的人机大战贪吃蛇。
会动的蛇
首先我们先实现一条能根据输入移动的蛇。
这条蛇的伪代码如下：
输出字符矩阵
WHILE not 游戏结束 DO
ch＝等待输入
CASE ch DO
‘A’:左前进一步，break
‘D’:右前进一步，break
‘W’:上前进一步，break
‘S’:下前进一步，break
END CASE
输出字符矩阵
END WHILE
输出 Game Over!!! 在实现时，首先管理好程序的头部：
#define SNAKE_MAX_LENGTH 20
#define SNAKE_HEAD 'H'
#define SNAKE_BODY 'X'
#define BLANK_CELL ' '
#define SNAKE_FOOD '$'
#define WALL_CELL '*'
#define MAP_SIZE 12
//snake stepping: dy = -1(up), 1(down); dx = -1(left), 1(right), 0(no move)
void snakeMove(int, int);
// put a food randimized on a blank cell
void put_money(void);
//output cells of the grid
void output(void);
//output gameover
void gameover(void);
char map[MAP_SIZE][MAP_SIZE] =
{
"************",
"*XXXXH *",
"* *",
"* *",
"* *",
"* *",
"* *",
"* *",
"* *",
"* *",
"* *",
"************",
};
// variables for snake and the initial values
int snakeX[SNAKE_MAX_LENGTH] = {1, 2, 3, 4, 5};
int snakeY[SNAKE_MAX_LENGTH] = {1, 1, 1, 1, 1};
int snakeLength = 5;
int isGameOver = 0;然后按伪代码编写 main 函数：
int main(int argc, const char * argv[]) {
char c;
output();
while (isGameOver == 0) { // if game is not over
scanf("%c", &c); //
while (c == '\n') {
scanf("%c", &c);
}
switch(c){
case 'a':
snakeMove(-1, 0);
break;
case 'd':
snakeMove(1, 0);
break;
case 'w':
snakeMove(0, 1);
break;
case 's':
snakeMove(0, -1);
break;
default:
break;
}
output();
}
gameover();
return 0;
}然后一个个实现 main 中的函数：
void snakeMove(int dx, int dy){
int i = snakeLength - 1;
// check if snake is going backward
if (snakeX[i] + dx == snakeX[i - 1] && snakeY[i] - dy == snakeY[i - 1]) {
return;
}
i = 0;
// turn TAIL into ' '
map[snakeY[i]][snakeX[i]] = ' ';
// make every BODY move forward
for (i = 0; i < snakeLength-1; i ++) {
snakeX[i] = snakeX[i+1];
snakeY[i] = snakeY[i+1];
}
// display every BODY
for (i = 1; i < snakeLength - 1; i ++) {
map[snakeY[i]][snakeX[i]] = SNAKE_BODY;
}
// make HEAD move
snakeX[i] += dx;
snakeY[i] -= dy;
// check if HEAD is moving to somewhere blank
if (map[snakeY[i]][snakeX[i]] != ' ') {
isGameOver = 1; // if not, game over
return;
}
// if so, display HEAD
map[snakeY[i]][snakeX[i]] = SNAKE_HEAD;
}
void output(void){
//system("clear && printf '\e[3J'");
//system("clear && '\e[3J'");
//system("\033[2J");
//system("\e[3J");
// if in windows environment, change the statement into:
// system("cls");
int i = 0, j = 0;
for (i = 0 ; i < MAP_SIZE; i ++) {
for (j = 0; j < MAP_SIZE; j ++) {
printf("%c",map[i][j]);
}
printf("\n");
}
}
void gameover(void){
printf("Game Over!");
}能吃的蛇
接下来就要让这条蛇有吃东西的功能了。
首先需要实现一个在空白位置放食物的函数：
void put_money(void){
if (isFoodEaten) {
foodX = rand() % 10 + 1;
foodY = rand() % 10 + 1;
while (map[foodY][foodX] != ' ') {
foodX = rand() % 10 + 1;
foodY = rand() % 10 + 1;
}
map[foodY][foodX] = SNAKE_FOOD;
isFoodEaten = 0;
}
}并修改 snakeMove 函数：
void snakeMove(int dx, int dy){
int i = snakeLength - 1;
// check if snake is going backward
if (snakeX[i] + dx == snakeX[i - 1] && snakeY[i] - dy == snakeY[i - 1]) {
return;
}
// check if snake is eating the food
if (map[snakeY[i] - dy][snakeX[i] + dx] == '$'){
map[snakeY[i] - dy][snakeX[i] + dx] = 'H';
map[snakeY[i]][snakeX[i]] = 'X';
snakeLength += 1;
// add HEAD position
snakeX[snakeLength-1] = snakeX[i] + dx;
snakeY[snakeLength-1] = snakeY[i] - dy;
isFoodEaten = 1;
return;
}
i = 0;
// turn TAIL into ' '
map[snakeY[i]][snakeX[i]] = ' ';
// make every BODY move forward
for (i = 0; i < snakeLength-1; i ++) {
snakeX[i] = snakeX[i+1];
snakeY[i] = snakeY[i+1];
}
// display every BODY
for (i = 1; i < snakeLength - 1; i ++) {
map[snakeY[i]][snakeX[i]] = SNAKE_BODY;
}
// make HEAD move
snakeX[i] += dx;
snakeY[i] -= dy;
// check if HEAD is moving to somewhere blank
if (map[snakeY[i]][snakeX[i]] != ' ') {
isGameOver = 1; // if not, game over
return;
}
// if so, display HEAD
map[snakeY[i]][snakeX[i]] = SNAKE_HEAD;
}可玩的贪吃蛇
能吃的蛇距离可玩的贪吃蛇游戏还有一些距离。主要问题在于蛇不能每个一端时间自动前进；并且输入时还需要摁回车确认。
我参考了这篇文章：Linux下非阻塞地检测键盘输入的方法 (整理)，在原来的基础上加入了 kbhit() 功能，解决上面的问题。
具体代码如下：
//
// main.c
// snake_play1
//
// Created by 尤大智 on 2017/12/24.
// Copyright © 2017年 尤大智. All rights reserved.
//
#include 于是一个如下图所示的字符版本贪吃蛇游戏就实现了：
创新玩法：人机大战贪吃蛇
利用此前实现的智能蛇程序，我想到可以把它加进游戏，使玩家和这只蛇对战一下，看看谁能活得更久，吃得更多。
具体代码如下：
//
// main.c
// snake_battle
//
// Created by 尤大智 on 2017/12/26.
// Copyright © 2017年 尤大智. All rights reserved.
//
#include