I'll help you set up the project with the linked list implementation in C. Here's the complete project structure: #ifndef LISTS_H #define LISTS_H typedef struct player { int player_id; int exp_points; struct player *next; } player_t; typedef struct list { player_t *head; player_t *tail; } list_t; list_t *create_empty_list(); void add_at_head(list_t *list, int player_id, int exp_points); void add_at_tail(list_t *list, int player_id, int exp_points); void insert(list_t *list, int player_id, int exp_points); int get_exp_points(list_t *list, int target_player_id); void print_list(list_t *list); void delete(list_t *list, int player_id); #endif #include #include #include #include "lists.h" list_t *create_empty_list() { list_t *list = calloc(1, sizeof(list_t)); return list; } void add_at_head(list_t *list, int player_id, int exp_points) { player_t *new_player = calloc(1, sizeof(player_t)); new_player->player_id = player_id; new_player->exp_points = exp_points; if (list->head == NULL) { list->head = new_player; list->tail = new_player; } else { new_player->next = list->head; list->head = new_player; } } void add_at_tail(list_t *list, int player_id, int exp_points) { player_t *new_player = calloc(1, sizeof(player_t)); new_player->player_id = player_id; new_player->exp_points = exp_points; if (list->tail == NULL) { list->head = new_player; list->tail = new_player; } else { list->tail->next = new_player; list->tail = new_player; } } void insert(list_t *list, int player_id, int exp_points) { player_t *new_player = calloc(1, sizeof(player_t)); new_player->player_id = player_id; new_player->exp_points = exp_points; if (list->head == NULL) { list->head = new_player; list->tail = new_player; return; } player_t *curr = list->head; player_t *prev = NULL; while (curr != NULL && curr->player_id < player_id) { prev = curr; curr = curr->next; } if (prev == NULL) { new_player->next = list->head; list->head = new_player; } else if (curr == NULL) { list->tail->next = new_player; list->tail = new_player; } else { prev->next = new_player; new_player->next = curr; } } int get_exp_points(list_t *list, int target_player_id) { player_t *p = list->head; while (p != NULL) { if (p->player_id == target_player_id) { return p->exp_points; } p = p->next; } return -1; } void print_list(list_t *list) { player_t *p = list->head; while (p != NULL) { printf("%d: %d\n", p->player_id, p->exp_points); p = p->next; } } void delete(list_t *list, int player_id) { if (list->head == NULL) { fprintf(stderr, "Error: list is empty\n"); return; } player_t *curr = list->head; player_t *prev = NULL; while (curr != NULL && curr->player_id != player_id) { prev = curr; curr = curr->next; } if (curr == NULL) { fprintf(stderr, "Error: player %d not found\n", player_id); return; } if (prev == NULL) { list->head = curr->next; } else { prev->next = curr->next; } if (curr == list->tail) { list->tail = prev; } free(curr); } #include #include #include #include "lists.h" int main() { // Test create_empty_list list_t *first_list = create_empty_list(); // Test add_at_head add_at_head(first_list, 16, 42); add_at_head(first_list, 18, 62); add_at_head(first_list, 4, 20); print_list(first_list); // Test get_exp_points int player_ids[] = {42, 78, 14, 36}; int player_exp_points[] = {16, 96, 43, 59}; list_t *search_list = create_empty_list(); for (int i = 0; i < 4; i++) { add_at_head(search_list, player_ids[i], player_exp_points[i]); } for (int i = 0; i < 4; i++) { int exp_points = get_exp_points(search_list, player_ids[i]); assert(exp_points == player_exp_points[i]); } // Test insert list_t *ordered_list = create_empty_list(); for (int i = 0; i < 4; i++) { insert(ordered_list, player_ids[i], player_exp_points[i]); } player_t *p = ordered_list->head; while (p->next != NULL) { assert(p->player_id < p->next->player_id); p = p->next; } // Test delete delete(ordered_list, 14); delete(ordered_list, 78); print_list(ordered_list); return 0; }