linkedlist_threads.c

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

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

typedef struct node{
    int data;
    struct node* next;
} node;

typedef struct __myarg_t {
    int data;
    struct node* head;
} myarg_t;

void print_list(node* head)
{
    node* cursor = head;
    while(cursor != NULL)
    {
        printf("%d ", cursor->data);
        cursor = cursor->next;
    }
}

node* create(int data,node* next)
{
    node* new_node = (node*)malloc(sizeof(node));
    if(new_node == NULL)
    {
        printf("Error creating a new node.\n");
        exit(0);
    }
    new_node->data = data;
    new_node->next = next;
 
    return new_node;
}

node* append(node* head, int data)
{
    /* go to the last node */
    node *cursor = head;
    while(cursor->next != NULL)
        cursor = cursor->next;
 
    /* create a new node */
    node* new_node =  create(data,NULL);
    cursor->next = new_node;
 
    return head;
}

node* remove_front(node* head)
{
    if(head == NULL)
        return NULL;
    node *front = head;
    head = head->next;
    front->next = NULL;
    /* is this the last node in the list */
    if(front == head)
        head = NULL;
    free(front);
    return head;
}

node* remove_back(node* head)
{
    if(head == NULL)
        return NULL;
 
    node *cursor = head;
    node *back = NULL;
    while(cursor->next != NULL)
    {
        back = cursor;
        cursor = cursor->next;
    }
    if(back != NULL)
        back->next = NULL;
 
    /* if this is the last node in the list*/
    if(cursor == head)
        head = NULL;
 
    free(cursor);
 
    return head;
}

void *mythread(void *arg)
{
    myarg_t *m = (myarg_t *) arg;
    while(m->data < 101){
        pthread_mutex_lock(&mutex);
        m->head = append(m->head, m->data);
        m->data += 1;
        pthread_mutex_unlock(&mutex);
    }
    return NULL;
}

int main(void)
{
    node* head = NULL;
    // inserte código para agregar 100 nodos
    // primero secuencialmente (usando un ciclo)
    // luego en paralelo

    head = create(0, NULL);
    if(head == NULL)
    {
        printf("Error creating a new node.\n");
        exit(0);
    }

    pthread_t p1;
    pthread_t p2;

    myarg_t args;
    args.head = head;
    args.data = 1;

    pthread_create(&p1, NULL, mythread, &args);
    pthread_create(&p2, NULL, mythread, &args);

    pthread_join(p1, NULL);
    pthread_join(p2, NULL);

    print_list(head);
    printf("\nListo!\n");
    return 0;
}