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

struct node {
  int value;
  struct node *next;
};

typedef struct node *tlista;

void print_list(tlista head) {
  tlista current = head;

  if(current == NULL){
    printf("NULL\n");
  }

  while (current != NULL) {
    printf("%d -> ", current->value);
    current = current->next;
    if(!current){
      printf("NULL\n");
    }
  }
  printf("\n");
}

void pushLast(tlista head){
  tlista current = head;
  while (current->next != NULL){
    current = current->next;
  }

  current->next = head;
}

void push(tlista head, int val) {
  tlista current = head;
  while (current->next != NULL) {
    current = current->next;
  }

  /* now we can add a new variable */
  current->next = (tlista)malloc(sizeof(struct node));
  current->next->value = val;
  current->next->next = NULL;
}

void free_list(tlista head) {
  tlista tmp;

  while (head != NULL) {
    tmp = head;
    head = head->next;
    free(tmp);
  }
}

int main(){
  tlista l1 = NULL;
  l1 = malloc(sizeof(struct node));
  l1->value = 4;
  l1->next = NULL;

  push(l1, 6);
  push(l1, 2);
  push(l1, 6);
  push(l1, 7);
  push(l1, 9);
  pushLast(l1);

  printf("lista1: ");
  print_list(l1);

  free(l1);

  return 0;
}