lista

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


#define N 10

typedef struct _list
{
    struct _list *next;
    int value;
}LIST;

void list_insert(LIST** head, int val)
{
    if(*head != NULL)
    {
        LIST* tmp = *head;
        while(tmp->next != NULL)
            tmp = tmp->next;
        tmp->next = calloc(1,sizeof(LIST));
        tmp->next->value = val;
    }else
    {
        *head = calloc(1,sizeof(LIST));
        (*head)->value = val;
    }
}

void list_print(LIST* head)
{
    LIST* tmp = head;
    printf("List contents: ");
    while(tmp->next != NULL)
    {
        printf("%d ",tmp->value);
        tmp = tmp->next;
    }
    printf("%d \n", tmp->value);
}

void list_dellast(LIST* head)
{
    LIST* tmp = head, *prev;
    do
    {
        prev = tmp;
        tmp = tmp->next;
    }while(tmp->next != NULL);

    free(tmp);
    prev->next = NULL;
}

int list_len(LIST* head)
{
    LIST* tmp = head;
    int l = 0;
    while(tmp != NULL)
    {
        l++;
        tmp = tmp->next;
    }
    return l;
}

void list_middleinsert(LIST* head, int val)
{
    int pos = list_len(head)/2, i;
    printf("\nInsert position found at %d\n",pos);
    LIST* tmp = head;
    for(i=1;i<pos && tmp != NULL;i++,tmp=tmp->next);
    LIST* new_elem = calloc(1,sizeof(LIST));
    new_elem->next = tmp->next;
    tmp->next = new_elem;
    new_elem->value = val;
}

void list_free(LIST* head)
{
    LIST* tmp = head, *tmp2;
    while(tmp->next != NULL)
    {
        tmp2 = tmp->next;
        free(tmp);
        tmp = tmp2;
    }
    free(tmp);
}

int main()
{

    srand(time(NULL));

    int numbers[N], i;
    for(i=0;i<N;i++)numbers[i] = rand()%100;

    LIST* lista = NULL;

    for(i=0;i<N;i++)
        list_insert(&lista,numbers[i]);

    printf("\nbefore: ");
    list_print(lista);
    printf("length = %d\n",list_len(lista));
    list_middleinsert(lista,2137);
    printf("\nafter: ");
    list_print(lista);
    printf("length = %d\n",list_len(lista));

    list_free(lista);

    return 0;
}