create BT needs a tweak - c

Question

Edit : the code works with this edit but I don't understand as to why it does.
working ideone with edit : http://ideone.com/ESfkrs
Edited code :
typedef struct _q{
int front,rear;
tree *a[MAX];
}queue;
void enqueue(queue *q, tree *x){
if(!q || q->rear==MAX-1 || !x){
return;
}
q->a[++q->rear]=x;
}
tree* dequeue(queue *q){
if(q->front>q->rear || q->front==MAX){
return NULL;
}
return q->a[q->front++];
}
I'v following code for creating a BT out of an array representation.
problem is that in multiple loops of while 1 level of BT nodes don't point to next level. i.e r->l & r->r is lost in transition of loop although the mem is heap allocated & must be retained until the program exits.
I'v spent umpteen hours digging this but to no vain. TIA.
working ideone : http://ideone.com/O4VKCH
output :
5 10 20
5 10 20
5 10 20
5 10 20
5 10 20
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 100
typedef struct _tree{
int data;
struct _tree *l,*r;
}tree;
typedef struct _q{
int front,rear;
tree a[MAX];
}queue;
void create_node(tree **rooty,int data){
(*rooty) = (tree*)calloc(1,sizeof(tree));
(*rooty)->data=data;
return;
}
void create_node_bst(tree **rooty,int data){
if(!(*rooty)) {
create_node(rooty,data);
}
if(data<(*rooty)->data) create_node_bst(&(*rooty)->l,data);
if(data>(*rooty)->data) create_node_bst(&(*rooty)->r,data);
}
void inorder(tree *root){
if(!root) return;
if(root->l) inorder(root->l);
printf("%d\t",root->data);
if(root->r) inorder(root->r);
}
void enqueue(queue *q, tree *x){
if(!q || q->rear==MAX-1 || !x){
return;
}
q->a[++q->rear]=*x;
}
tree* dequeue(queue *q){
if(q->front>q->rear || q->front==MAX){
return NULL;
}
return &(q->a[q->front++]);
}
void print_q(queue *q){
if(!q || q->front>q->rear){
return;
}
int front=q->front;
printf("+\n");
while(front<=q->rear){
printf("%d\t",q->a[front++].data);
}
printf("\n-");
}
void bfs_order(tree *root, queue *q){
if(!root || !q){
return;
}
printf("%d\t",root->data);
if(root->l)enqueue(q,root->l);
if(root->r)enqueue(q,root->r);
bfs_order(dequeue(q),q);
}
void initialise_q(queue **q){
if(!*q){
*q = (queue*)malloc(sizeof(queue));
(*q)->front=0;
(*q)->rear=-1;
memset((*q)->a,0,MAX*sizeof(int));
}
}
tree* create_bt(tree *r, queue *q, int *arr, int len){
if(!q || !arr) return NULL;
int i=0,first=1;
tree *root=NULL, *ret=NULL;
while(i<len){
tree *temp_l=NULL, *temp_r=NULL;
root = dequeue(q);
if(first){
ret = root;
first = 0;
}
if(!root) break;
if(i+1<len) {
create_node(&temp_l,arr[i+1]);
enqueue(q,temp_l);
}
if(i+2<len) {
create_node(&temp_r,arr[i+2]);
enqueue(q,temp_r);
}
if(temp_l) {
//root->l=temp_l;
create_node(&(root->l),temp_l->data); <-- Pls focus here
}
if(temp_r) {
//root->l=temp_r;
create_node(&(root->r),temp_r->data); <-- llly, here.
}
inorder(ret); printf("\n"); <-- to demo the output
i+=2;
}
return ret;
}
int main(void) {
tree *root = NULL, *temp_t=NULL;
int arr[]={10,5,20,2,7,8,9,0,1};
int len = sizeof(arr)/sizeof(arr[0]);
for(int k=0;k<len;k++){
//create_node_bst(&root,arr[k]);
}
queue *q = NULL, *temp_q=NULL;
initialise_q(&q);
initialise_q(&temp_q);
create_node(&temp_t,arr[0]);
enqueue(q,temp_t);
tree *bt = create_bt(root,q,arr,len);
//bfs_order(bt,temp_q);
if(root) free(root);
if(q) free(q);
return 0;
}