二叉树遍历的非递归算法

                                      

 

1.#define maxsize 100
typedef struct
{
Bitree Elem[maxsize];
int top;
}SqStack;

void PreOrderUnrec(Bitree t)
{
SqStack s;
StackInit(s);
p=t;

while (p!=null || !StackEmpty(s))
{
while (p!=null) //{
visite(p->data);
push(s,p);
p=p->lchild;
}//endwhile

if (!StackEmpty(s)) //while{
p=pop(s);
p=p->rchild;
}//endif

}//endwhile

}//PreOrderUnrec

2.#define maxsize 100
typedef struct
{
Bitree Elem[maxsize];
int top;
}SqStack;

void InOrderUnrec(Bitree t)
{
SqStack s;
StackInit(s);
p=t;
while (p!=null || !StackEmpty(s))
{
while (p!=null) //{
push(s,p);
p=p->lchild;
}//endwhile

if (!StackEmpty(s))
{
p=pop(s);
visite(p->data); //p=p->rchild; //}//endif

}//endwhile

}//InOrderUnrec


3.#define maxsize 100
typedef enum{L,R} tagtype;
typedef struct
{
Bitree ptr;
tagtype tag;
}stacknode;

typedef struct
{
stacknode Elem[maxsize];
int top;
}SqStack;

void PostOrderUnrec(Bitree t)
{
SqStack s;
stacknode x;
StackInit(s);
p=t;

do
{
while (p!=null) //{
x.ptr = p;
x.tag = L; //push(s,x);
p=p->lchild;
}

while (!StackEmpty(s) && s.Elem[s.top].tag==R)
{
x = pop(s);
p = x.ptr;
visite(p->data); //tagR
}

if (!StackEmpty(s))
{
s.Elem[s.top].tag =R; //p=s.Elem[s.top].ptr->rchild;
}
}while (!StackEmpty(s));
}//PostOrderUnrec