A linked list in C

linkedlist.c

// This is the code for linked list in C.
// This includes functions for insert,delete,search and traverse
// I used the distribution code from my course CS50 by Porf.David.J.Malan
#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

// Defines a node for linked list
typedef struct node
{
    int n;
    struct node* next;
}
node;

// linked list
node* first = NULL;

// prototypes
void delete(void);
void insert(void);
void search(void);
void traverse(void);