二叉树的非递归遍历

来源：互联网发布：单片机工程师月薪多少编辑：程序博客网时间：2024/06/03 20:28

/*二叉树的非递归遍历算法*/
/*注意指针的使用*/

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

#define OK 1
#define ERROR 0
#define Start 2
#define Left 3
#define Right 4
#define MAXSIZE 50

typedef int Status;
typedef char ElemType;
/******************* 树 *******************/
typedef struct BiNode
{
struct BiNode *lchild;
struct BiNode *rchild;
ElemType data;
int flag;
}BiNode,*BiTree;
Status CreateTree(BiTree &T)
{
ElemType c;
scanf("%c",&c);
if(c=='#') T=NULL;
else
{
  T=(BiNode*)malloc(sizeof(BiNode));
  T->data=c;
  CreateTree(T->lchild);
  CreateTree(T->rchild);
}
return OK;
}
Status PreOrder(BiTree T)
{
if(T!=NULL)
{
  if(T->data!='#') printf("%c ",T->data);
  PreOrder(T->lchild);
  PreOrder(T->rchild);
}
return OK;
}
Status InOrder(BiTree T)
{
if(T!=NULL)
{
  InOrder(T->lchild);
  if(T->data!='#') printf("%c ",T->data);
  InOrder(T->rchild);
}
return OK;
}
Status PoOrder(BiTree T)
{
if(T!=NULL)
{
  PoOrder(T->lchild);
  PoOrder(T->rchild);
  if(T->data!='#') printf("%c ",T->data);
}
return OK;
}
/***********************************************/
/*********************** 栈 **********************/
typedef BiTree SElemType;
typedef struct Stack
{
SElemType *base;
SElemType *top;
int maxsize;
}Stack;
Status InitStack(Stack *S)
{
S->base=(SElemType*)malloc(sizeof(SElemType)*MAXSIZE);
S->top=S->base;
S->maxsize=MAXSIZE;
return OK;
}
bool StackEmpty(Stack *S)
{
if(S->base == S->top) return 1;
return 0;
}
Status Push(Stack *S,SElemType e)
{
if(S->top - S->base >= S->maxsize)
{
  printf("OVERFLOW!\n");
  return ERROR;
}
e->flag=Start;
*S->top++=e;
return OK;
}
Status Pop(Stack *S,SElemType *e)
{
if(StackEmpty(S)) return ERROR;
*e=*S->top--;
return OK;
}
Status GetTop(Stack *S,SElemType *e)
{
*e=*(S->top-1);
return OK;
}
/*************************************************/
/******************************/
Status Visite(BiTree T,int kind)
{
if(kind==1) printf("先序算法（非递归）:\n");
else if(kind==2) printf("中序算法（非递归）:\n");
else if(kind == 3) printf("后序算法（非递归）:\n");
Stack S;
InitStack(&S);
SElemType e;
Push(&S,T);
while(!StackEmpty(&S))
{
  GetTop(&S,&e);
  if(e->flag==Start)
  {
   e->flag=Left;
   if(kind ==1) printf("%c ",e->data);
   if(e->lchild!=NULL)
   {
    Push(&S,e->lchild);
   }
  }
  else if(e->flag==Left)
  {
   if(kind==2) printf("%c ",e->data);
   e->flag=Right;
   if(e->rchild!=NULL)
   {
    Push(&S,e->rchild);
   }
  }
  else if(e->flag==Right)
  {
   if(kind==3) printf("%c ",e->data);
   Pop(&S,&e);
  }
}
printf("\n");
return OK;
}
/******************************/
int main()
{
BiTree T;
CreateTree(T);
PreOrder(T);
printf("\n");
InOrder(T);
printf("\n");
PoOrder(T);
printf("\n");
/***************/

/***************/
Visite(T,1);
Visite(T,2);
Visite(T,3);
return 0;
}

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