6.37③ test directly using the basic operation of the stack to write the first-order traversal of the non-recursive form of the algorithm _ Guang-gong

6.37③ test directly using the basic operation of the stack to write out the first order traversal of the non-recursive
The form of the algorithm (hint: Do not have to press 3.3.2 section from recursive to non-recursive
Method and write the non recursive algorithm directly.


Requires that the following functions be implemented:
void Preorder (Bitree bt, Void (*visit) (Telemtype));
/* Using the stack, non-recursive first-order traversal of the binary tree bt, * *
/* The element domain data call function for each node visit * *


Binary link list type definition:
typedef struct BITNODE {
Telemtype data;
Bitnode *lchild,*rchild;
} Bitnode, *bitree;


The relevant definitions of stack type stacks available:
typedef bitree SELEMTYPE; The element type of the stack


Status Initstack (Stack &s);
Status stackempty (Stack S);
Status Push (Stack &s, Selemtype e);
Status POPs (Stack &s, Selemtype &e);

Status GetTop (Stack S, Selemtype &e);

Void Preorder (Bitree bt, Void (*visit) (Telemtype)  
/* using stacks, non-recursive first-order traversal of binary tree bt,    */
/* The element domain data call function for each node visit */
{
   //The node is pushed into the stack to facilitate access to the node's right node
    Bitree p = bt;
  &NBSP ; Stack s;   &NBSP
    Initstack (s);
    while (P | |!) Stackempty (s)) {
        if (p) {
            Visit (p->data)
            Push (S, p);
           -P = p->lchild;
       }else{
            POP (S, p);
            p = p->rchild;
       }                 
   
}