/* Programul creeaza o lista dublu inlantuita */

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

struct lista
	{int k;
	 struct lista *next,*prev;
	 };

struct lista *cons_ldi(int k,struct lista *l)
{ 	struct lista *aux;
	aux=(struct lista *)malloc(sizeof(struct lista));
	aux->k=k;
	aux->next=l;
	aux->prev=NULL;
	if(l) l->prev=aux;
	return(aux);
}

struct lista *init_ldi(struct lista *l)
{
	int ci,k;
	char c,ck,cc[5];
	l=NULL;

	printf("Doriti sa incepeti initializarea listei [n pentru terminare]?");
	scanf("%c",&c);
	if (c!='n')
	   k=1;
	else
	   k=-1;
	while (k!=-1)
	{
		printf(" o cheie : ");
		scanf("%s",cc);
		if (strcmp(cc,"n"))
		   k=1;
		else
		   k=-1;
		ci=atoi(cc);
		if(k!=-1)
		   l=cons_ldi(ci,l);
	}
	return(l);
}

void tipar_ldi(struct lista *l)
{ 	 struct lista *p;
	 printf("NULL");
	 for (p=l;p;p=p->next)printf("<=>%d",p->k);
	 printf("<=>NULL\n");
}

struct lista *inserare(struct lista *l, int poz, int inf){
    struct lista *aux;
    struct lista *p;

      aux=(struct lista *)malloc(sizeof(struct lista));
      aux->k=inf;
      if(poz==1){
        aux->prev=NULL;
        aux->next=l;
        if(l!=NULL)
            l->prev=aux;
            l=aux;
      }
      else{
        p=l;
        for(int i=1;i<=poz-2&&p!=NULL;i++)
            p=p->next;

          aux->next=p->next;
          if(p->next!=NULL)
          p->next->prev=aux;
          p->next=aux;
          aux->prev=p;
}
return l;




};

int main()
{
        struct lista *l;
		int k;

		l=init_ldi(l);
		printf(" \n \n LISTA INITIALA : ");
		tipar_ldi(l);
		l=inserare(l,3,3333);
		printf(" \n \n LISTA DUPA INSERTIE : ");
		tipar_ldi(l);

    	return 0;
}