写一个贪吃蛇的小游戏程序，用c语言

下面是一个简单的贪吃蛇小游戏程序，使用C语言编写：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <conio.h>
#include <windows.h>

#define WIDTH 30
#define HEIGHT 20
#define SNAKE_MAX_LENGTH (WIDTH * HEIGHT)

typedef struct _Point {
    int x;
    int y;
} Point;

typedef struct _Snake {
    int length;
    Point body[SNAKE_MAX_LENGTH];
} Snake;

typedef enum _Direction {
    UP,
    DOWN,
    LEFT,
    RIGHT
} Direction;

Point food;
Snake snake;
Direction direction = RIGHT;

void gotoxy(int x, int y) {
    COORD pos = { x, y };
    HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
    SetConsoleCursorPosition(hOut, pos);
}

void initGame() {
    srand((unsigned)time(NULL));

    // 初始化蛇
    snake.body[0] = (Point) { 10, 10 };
    snake.body[1] = (Point) { 9, 10 };
    snake.body[2] = (Point) { 8, 10 };
    snake.length = 3;

    // 初始化食物
    food.x = rand() % WIDTH;
    food.y = rand() % HEIGHT;
}

void draw() {
    system("cls");
    for (int i = 0; i < WIDTH + 2; i++) {
        printf("#");
    }
    printf("\n");

    for (int y = 0; y < HEIGHT; y++) {
        printf("#");
        for (int x = 0; x < WIDTH; x++) {
            if (x == snake.body[0].x && y == snake.body[0].y) {
                printf("O");
            }
            else if (x == food.x && y == food.y) {
                printf("*");
            }
            else {
                int isBody = 0;
                for (int i = 1; i < snake.length; i++) {
                    if (x == snake.body[i].x && y == snake.body[i].y) {
                        printf("o");
                        isBody = 1;
                        break;
                    }
                }
                if (!isBody) {
                    printf(" ");
                }
            }
        }
        printf("#\n");
    }

    for (int i = 0; i < WIDTH + 2; i++) {
        printf("#");
    }
    printf("\n");
}

void update() {
    // 判断是否吃到食物
    if (snake.body[0].x == food.x && snake.body[0].y == food.y) {
        for (int i = snake.length; i > 0; i--) {
            snake.body[i] = snake.body[i - 1];
        }
        snake.length++;
        food.x = rand() % WIDTH;
        food.y = rand() % HEIGHT;
    }

    // 更新蛇的位置
    for (int i = snake.length - 1; i > 0; i--) {
        snake.body[i] = snake.body[i - 1];
    }
    switch (direction) {
        case UP:
            snake.body[0].y--;
            break;
        case DOWN:
            snake.body[0].y++;
            break;
        case LEFT:
            snake.body[0].x--;
            break;
        case RIGHT:
            snake.body[0].x++;
            break;
    }

    // 判断是否碰到墙
    if (snake.body[0].x < 0 || snake.body[0].x >= WIDTH || snake.body[0].y < 0 || snake.body[0].y >= HEIGHT) {
        printf("Game Over!\n");
        exit(0);
    }

    // 判断是否碰到自己的身体
    for (int i = 1; i < snake.length; i++) {
        if (snake.body[0].x == snake.body[i].x && snake.body[0].y == snake.body[i].y) {
            printf("Game Over!\n");
            exit(0);
        }
    }
}

void input() {
    if (_kbhit()) {
        switch (_getch()) {
            case 'w':
            case 'W':
                if (direction != DOWN) {
                    direction = UP;
                }
                break;
            case 's':
            case 'S':
                if (direction != UP) {
                    direction = DOWN;
                }
                break;
            case 'a':
            case 'A':
                if (direction != RIGHT) {
                    direction = LEFT;
                }
                break;
            case 'd':
            case 'D':
                if (direction != LEFT) {
                    direction = RIGHT;
                }
                break;
            default:
                break;
        }
    }
}

int main() {
    initGame();
    while (1) {
        draw();
        update();
        input();
        Sleep(100);
    }
    return 0;
}

该程序使用了Windows API的一些函数，因此只能在Windows平台下运行。在Windows下，可以使用Visual Studio等集成开发环境编译运行。