Code - Battle Royale Demo part 2

// Battle Royale Linked List Demo

// Part 1: Creating a linked list using a function
// that creates a single node.
// Looping through the list and printing out the names

// Part 2: Inserting into the linked list.
// Also finding specific insertion points and
// inserting into an ordered list

// Marc Chee (cs1511@cse.unsw.edu.au) November 2020

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

#define MAX_NAME_LENGTH 100

struct player {
    struct player *next;
    char name[MAX_NAME_LENGTH];
};

struct player *create_player(char *newName, struct player *newNext);
void printPlayers(struct player *playerList);
struct player *insert_after(struct player *insert_pos, char *newName);
struct player *insert_alpha(struct player *list, char *newName);

int main(void) {
    struct player *head = NULL;        
    head = insert_alpha(head, "Marc");
    printPlayers(head);
    printf("--------------\n");
    head = insert_alpha(head, "Chicken");
    printPlayers(head);
    printf("--------------\n");
    head = insert_alpha(head, "Aang");
    printPlayers(head);
    printf("--------------\n");
    head = insert_alpha(head, "Zuko");    
    printPlayers(head);
    printf("--------------\n");
    head = insert_alpha(head, "Katara");    
    printPlayers(head);
    return 0;
}

// create player allocates memory for a new player and
// populates it with newName and newNext.
// returns a pointer the the newly created player
struct player *create_player(char *newName, struct player *newNext) {
    struct player *newPlayer = malloc(sizeof (struct player));
    strcpy(newPlayer->name, newName);
    newPlayer->next = newNext;
    return newPlayer;
}

// takes the pointer to the head of a list of players
// prints their names, one per line
void printPlayers(struct player *playerList) {
    struct player *curr = playerList;
    while (curr != NULL) {
        //fputs(curr->name, stdout);
        //putchar('\n');
        printf("%s\n", curr->name);
        curr = curr->next;
    }
}

// Insert a newly created player after insert_pos in a list
// If the list was empty, return a pointer to the new list
// Otherwise, return insert_pos
struct player *insert_after(struct player *insert_pos, char *newName) {
    // create a new player
    struct player *new_player = create_player(newName, NULL);
    
    if (insert_pos == NULL) {
        // inserting into an empty list
        insert_pos = new_player;
        
    } else {
        // inserting into a list that exists
        // set the new player's next to be insert_pos' next
        new_player->next = insert_pos->next;
        
        // set insert_pos' next to aim at the new player
        insert_pos->next = new_player;
    }
    
    return insert_pos;
}

// Insert an element into an already alphabetically ordered list
// Will insert into the correct position, then return the head
// of the list, even if it has changed
struct player *insert_alpha(struct player *list, char *newName) {
    // loop through looking for the insertion point
    struct player *curr = list;
    struct player *prev = NULL;
    
    // stop when we see something that's after us in the alphabet
    while (curr != NULL && strcmp(newName, curr->name) > 0) {        
        prev = curr;
        curr = curr->next;
    }
    // prev now aims at where the insertion should happen
    
    // Use insert_after
    struct player *new_head = insert_after(prev, newName);
    
    if (prev == NULL) {
        // the new player is the head of the list
        new_head->next = list;        
    } else {
        // the new player is inserted somewhere other than the head
        new_head = list;
    }
    
    return new_head;
}