pvjc24/a2/snake.c

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

#define FOOD_COUNT 3
#define MAX_SNAKE_LENGTH 100

// Define the direction constants
#define UP    0
#define LEFT  1
#define DOWN  2
#define RIGHT 3

struct state {
    int width;
    int height;
    int snake_length;
    int snake_x[MAX_SNAKE_LENGTH];
    int snake_y[MAX_SNAKE_LENGTH];
    int foodx[FOOD_COUNT];
    int foody[FOOD_COUNT];
    int sx;
    int sy;
};

// Function prototypes
void init_state(struct state* state, int width, int height);
void draw_state(struct state* state);
void process_input(struct state* state);
int step_state(struct state* state);
void generate_food(struct state* state);
int is_snake(struct state* state, int x, int y);
void free_snake(struct state* state);

// Add a new segment to the snake
void add_snake(struct state* state, int x, int y) {
    state->snake_x[state->snake_length] = x;
    state->snake_y[state->snake_length] = y;
    state->snake_length++;
}

// Check if the given position is occupied by the snake
int is_snake(struct state* state, int x, int y) {
    for (int i = 0; i < state->snake_length; i++) {
        if (state->snake_x[i] == x && state->snake_y[i] == y) {
            return 1;
        }
    }
    return 0;
}

// Free the memory allocated for the snake
void free_snake(struct state* state) {
    // No dynamic memory allocation for the snake in this implementation
}

// Move the snake by one step
int step_state(struct state* state) {
    // Move the snake body
    for (int i = state->snake_length - 1; i > 0; i--) {
        state->snake_x[i] = state->snake_x[i - 1];
        state->snake_y[i] = state->snake_y[i - 1];
    }

    // Move the snake head
    state->snake_x[0] += state->sx;
    state->snake_y[0] += state->sy;

    // Check for collisions with walls
    if (state->snake_x[0] < 0 || state->snake_x[0] >= state->width ||
        state->snake_y[0] < 0 || state->snake_y[0] >= state->height) {
        return 1; // Collision with wall
    }

    // Check for collisions with itself
    for (int i = 1; i < state->snake_length; i++) {
        if (state->snake_x[i] == state->snake_x[0] && state->snake_y[i] == state->snake_y[0]) {
            return 2; // Collision with itself
        }
    }

    // Check for collisions with food
    for (int i = 0; i < FOOD_COUNT; i++) {
        if (state->snake_x[0] == state->foodx[i] && state->snake_y[0] == state->foody[i]) {
            // Increase the snake length
            state->snake_length++;
            if (state->snake_length >= MAX_SNAKE_LENGTH) {
                return 3; // Snake length exceeds the maximum
            }
            // Move the food to a new random position
            state->foodx[i] = rand() % state->width;
            state->foody[i] = rand() % state->height;
            return 0; // Food eaten
        }
    }

    return 0; // No collision
}

void init_state(struct state* state, int width, int height) {
    state->width = width;
    state->height = height;
    state->snake_length = 1;
    state->snake_x[0] = width / 2;
    state->snake_y[0] = height / 2;
    state->sx = 0;
    state->sy = -1; // Start moving upward
    for (int i = 0; i < FOOD_COUNT; i++) {
        state->foodx[i] = rand() % width;
        state->foody[i] = rand() % height;
    }
}

void generate_food(struct state* state) {
    for (int i = 0; i < FOOD_COUNT; i++) {
        state->foodx[i] = rand() % state->width;
        state->foody[i] = rand() % state->height;
    }
}

void draw_state(struct state* state) {
    for (int y = 0; y < state->height; y++) {
        for (int x = 0; x < state->width; x++) {
            if (x == state->snake_x[0] && y == state->snake_y[0]) {
                printf("H"); // Snake head
            } else if (is_snake(state, x, y)) {
                printf("S"); // Snake body
            } else {
                int is_food = 0;
                for (int i = 0; i < FOOD_COUNT; i++) {
                    if (state->foodx[i] == x && state->foody[i] == y) {
                        is_food = 1;
                        break;
                    }
                }
                printf(is_food ? "F" : ".");
            }
        }
        printf("\n");
    }
}