snake

cv9/snake.c

@@ -0,0 +1,82 @@
+#include "snake.h"
+#include <stdlib.h>
+
+
+struct snake* add_snake(struct snake* snake, int x, int y) {
+    struct snake* new_part = (struct snake*)malloc(sizeof(struct snake));
+    if (!new_part) return NULL;
+    new_part->x = x;
+    new_part->y = y;
+    new_part->next = snake;
+    return new_part;
+}
+
+
+struct snake* remove_snake(struct snake* snake) {
+    if (snake == NULL) return NULL;
+    if (snake->next == NULL) {
+        free(snake);
+        return NULL;
+    }
+    struct snake* current = snake;
+    while (current->next->next != NULL) {
+        current = current->next;
+    }
+    free(current->next);
+    current->next = NULL;
+    return snake;
+}
+
+
+int is_snake(struct snake* snake, int x, int y) {
+    struct snake* current = snake;
+    while (current != NULL) {
+        if (current->x == x && current->y == y)
+            return 1;
+        current = current->next;
+    }
+    return 0;
+}
+
+
+void free_snake(struct snake* snake) {
+    while (snake != NULL) {
+        struct snake* next = snake->next;
+        free(snake);
+        snake = next;
+    }
+}
+
+
+int step_state(struct state* state) {
+    int new_x = state->snake->x + state->sx;
+    int new_y = state->snake->y + state->sy;
+
+    if (new_x < 0 || new_x >= state->width || new_y < 0 || new_y >= state->height)
+        return END_WALL; 
+    if (is_snake(state->snake, new_x, new_y))
+        return END_SNAKE;
+
+
+    for (int i = 0; i < FOOD_COUNT; i++) {
+        if (state->foodx[i] == new_x && state->foody[i] == new_y) {
+            state->foodx[i] = state->foody[i] = -1;
+            state->snake = add_snake(state->snake, new_x, new_y);
+
+            int all_eaten = 1;
+            for (int j = 0; j < FOOD_COUNT; j++) {
+                if (state->foodx[j] != -1 || state->foody[j] != -1) {
+                    all_eaten = 0;
+                    break;
+                }
+            }
+            return all_eaten ? END_FOOD : END_CONTINUE;
+        }
+    }
+
+
+    state->snake = add_snake(state->snake, new_x, new_y);
+    state->snake = remove_snake(state->snake);
+    return END_CONTINUE;
+}
+