用C语言写一个贪吃蛇游戏程序

由于贪吃蛇游戏涉及到图形界面的显示等操作，需要使用相关的图形库，如SDL、OpenGL等。以下是一个使用SDL库实现的简单贪吃蛇游戏程序。

#include <SDL2/SDL.h>
#include <stdlib.h>
#include <time.h>

#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
#define BLOCK_SIZE 20

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

typedef enum {
    DIR_UP,
    DIR_DOWN,
    DIR_LEFT,
    DIR_RIGHT
} Direction;

SDL_Window *window = NULL;
SDL_Renderer *renderer = NULL;
SDL_Texture *block_texture = NULL;

int map[SCREEN_HEIGHT / BLOCK_SIZE][SCREEN_WIDTH / BLOCK_SIZE];
int score = 0;
Point snake[SCREEN_WIDTH * SCREEN_HEIGHT];
int snake_length = 3;
Direction snake_dir = DIR_RIGHT;
Point food;

void init() {
    srand(time(NULL));
    SDL_Init(SDL_INIT_VIDEO);
    window = SDL_CreateWindow("Snake", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
    renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
    block_texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, BLOCK_SIZE, BLOCK_SIZE);
    SDL_SetRenderTarget(renderer, block_texture);
    SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
    SDL_RenderClear(renderer);
    SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, 0xFF);
    SDL_RenderDrawLine(renderer, BLOCK_SIZE / 2, 0, BLOCK_SIZE / 2, BLOCK_SIZE);
    SDL_RenderDrawLine(renderer, BLOCK_SIZE / 2, BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE / 2);
    SDL_RenderDrawLine(renderer, BLOCK_SIZE, BLOCK_SIZE / 2, BLOCK_SIZE / 2, BLOCK_SIZE / 2);
    SDL_SetRenderTarget(renderer, NULL);
    for (int i = 0; i < snake_length; i++) {
        snake[i].x = SCREEN_WIDTH / 2 - BLOCK_SIZE * (snake_length - i);
        snake[i].y = SCREEN_HEIGHT / 2;
        map[snake[i].y / BLOCK_SIZE][snake[i].x / BLOCK_SIZE] = 1;
    }
    food.x = rand() % (SCREEN_WIDTH / BLOCK_SIZE) * BLOCK_SIZE;
    food.y = rand() % (SCREEN_HEIGHT / BLOCK_SIZE) * BLOCK_SIZE;
}

void quit() {
    SDL_DestroyTexture(block_texture);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
}

void draw_block(int x, int y) {
    SDL_Rect rect = {x, y, BLOCK_SIZE, BLOCK_SIZE};
    SDL_RenderCopy(renderer, block_texture, NULL, &rect);
}

void draw_map() {
    for (int i = 0; i < SCREEN_HEIGHT / BLOCK_SIZE; i++) {
        for (int j = 0; j < SCREEN_WIDTH / BLOCK_SIZE; j++) {
            if (map[i][j] == 1) {
                draw_block(j * BLOCK_SIZE, i * BLOCK_SIZE);
            }
        }
    }
}

void draw_snake() {
    SDL_SetRenderDrawColor(renderer, 0x00, 0xFF, 0x00, 0xFF);
    for (int i = 0; i < snake_length; i++) {
        draw_block(snake[i].x, snake[i].y);
    }
}

void draw_food() {
    SDL_SetRenderDrawColor(renderer, 0xFF, 0x00, 0x00, 0xFF);
    draw_block(food.x, food.y);
}

void move_snake() {
    Point head = snake[0];
    switch (snake_dir) {
        case DIR_UP:
            head.y -= BLOCK_SIZE;
            break;
        case DIR_DOWN:
            head.y += BLOCK_SIZE;
            break;
        case DIR_LEFT:
            head.x -= BLOCK_SIZE;
            break;
        case DIR_RIGHT:
            head.x += BLOCK_SIZE;
            break;
    }
    if (head.x < 0 || head.x >= SCREEN_WIDTH || head.y < 0 || head.y >= SCREEN_HEIGHT || map[head.y / BLOCK_SIZE][head.x / BLOCK_SIZE] == 1) {
        SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Game Over", "You Lose!", window);
        quit();
        exit(0);
    }
    snake_length++;
    for (int i = snake_length - 1; i > 0; i--) {
        snake[i] = snake[i - 1];
    }
    snake[0] = head;
    map[head.y / BLOCK_SIZE][head.x / BLOCK_SIZE] = 1;
    if (head.x == food.x && head.y == food.y) {
        score++;
        food.x = rand() % (SCREEN_WIDTH / BLOCK_SIZE) * BLOCK_SIZE;
        food.y = rand() % (SCREEN_HEIGHT / BLOCK_SIZE) * BLOCK_SIZE;
    } else {
        map[snake[snake_length - 1].y / BLOCK_SIZE][snake[snake_length - 1].x / BLOCK_SIZE] = 0;
    }
}

void handle_event(SDL_Event *event) {
    switch (event->type) {
        case SDL_QUIT:
            quit();
            exit(0);
            break;
        case SDL_KEYDOWN:
            switch (event->key.keysym.sym) {
                case SDLK_UP:
                    if (snake_dir != DIR_DOWN) {
                        snake_dir = DIR_UP;
                    }
                    break;
                case SDLK_DOWN:
                    if (snake_dir != DIR_UP) {
                        snake_dir = DIR_DOWN;
                    }
                    break;
                case SDLK_LEFT:
                    if (snake_dir != DIR_RIGHT) {
                        snake_dir = DIR_LEFT;
                    }
                    break;
                case SDLK_RIGHT:
                    if (snake_dir != DIR_LEFT) {
                        snake_dir = DIR_RIGHT;
                    }
                    break;
            }
            break;
    }
}

int main(int argc, char *argv[]) {
    init();
    SDL_Event event;
    while (1) {
        while (SDL_PollEvent(&event)) {
            handle_event(&event);
        }
        SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
        SDL_RenderClear(renderer);
        draw_map();
        draw_snake();
        draw_food();
        move_snake();
        SDL_RenderPresent(renderer);
        SDL_Delay(100);
    }
    return 0;
}
``