C++语言实现二叉树的非递归遍历

#include
#include
using namespace std;


typedef struct BiTNode
{
int data;
BiTNode *lchild,*rchild;
}BiTNode;


BiTNode* goLeft(BiTNode* T,stack &s)
{
if(T == NULL)
{
   return NULL;
}
//如果有左子树 入栈 返回起点
while(T->lchild)
{
   s.push(T);
T = T->lchild;
}
return T;
}


void inOrder01(BiTNode* T)
{
BiTNode* t = NULL;
stack s;
if(T == NULL)
{
   return;
}


//步骤1 找到左起点
t = goLeft(T,s);
while(t)
{
printf("%d ",t->data);
//如果有右子树 重复步骤1
if(t->rchild)
{
t = goLeft(t->rchild,s);
}
else if(!s.empty())
{
   t = s.top();
s.pop();
}
else
{
   t = NULL;
}
}
}


void preOrder01(BiTNode* T)
{
stack s;
BiTNode* t = NULL;
if(T == NULL)
{
  return;
}

t = T;
while(t)
{
   printf("%d ",t->data);


if(t->lchild)
{
if(t->rchild)
{
s.push(t->rchild);
}
t = t->lchild;
}
else if(t->rchild)
{
t = t->rchild;
}
else if(!s.empty())
{
   t = s.top();
s.pop();
}
else
{
   t = NULL;
}
}
}


void goLeft1(BiTNode* T,stack &s)
{
BiTNode* t = NULL;
if(T == NULL)
{
   return;
}


while(T)
{
   s.push(T);
t = T;
T = T->lchild;
if(T == NULL)
{
T = t->rchild;
}
}
}
void postOrder01(BiTNode* T)
{
stack s;
BiTNode* t = NULL;
BiTNode* tmp = NULL;
if(T == NULL)
{
   return;
}


goLeft1(T,s);

if(!s.empty())
{
   t = s.top();
}
while(t)
{
if(!t->rchild || t->rchild == tmp)
   {
      printf("%d ", t->data);
  tmp = t;
  s.pop();
  //t = s.top();
  if(!s.empty())
{
    t =  s.top();
}
else
{
   t = NULL;
}
   }
   else
   {
   goLeft1(t->rchild,s);
if(!s.empty())
{
    t =  s.top();
}
else
{
   t = NULL;
}
   }
}
}

void main()
{
BiTNode t1,t2,t3,t4,t5; //定义树的节点
memset(&t1,0,sizeof(BiTNode));
memset(&t2,0,sizeof(BiTNode));
memset(&t3,0,sizeof(BiTNode));
memset(&t4,0,sizeof(BiTNode));
memset(&t5,0,sizeof(BiTNode));
t1.data = 1;
t2.data = 2;
t3.data = 3;
t4.data = 4;
t5.data = 5;


//建立节点之间的关系
t1.lchild = &t2;
t1.rchild = &t3;
t2.lchild = &t4;
t3.lchild = &t5;


printf("非递归前序遍历\n");
preOrder01(&t1);
printf("\n");
printf("非递归中序遍历:\n");
inOrder01(&t1);
printf("\n");
printf("非递归后序遍历:\n");
postOrder01(&t1);
printf("\n");


{
   BiTNode t1,t2,t3,t4,t5,t6; //定义树的节点
memset(&t1,0,sizeof(BiTNode));
   memset(&t2,0,sizeof(BiTNode));
   memset(&t3,0,sizeof(BiTNode));
   memset(&t4,0,sizeof(BiTNode));
   memset(&t5,0,sizeof(BiTNode));
memset(&t6,0,sizeof(BiTNode));


t1.data = 1;
t2.data = 2;
t3.data = 3;
t4.data = 4;
t5.data = 5;
t6.data = 6;


t1.lchild = &t2;
t2.lchild = &t3;
t2.rchild = &t4;


t1.rchild = &t5;
t5.rchild = &t6;


printf("非递归前序遍历\n");
   preOrder01(&t1);
   printf("\n");
printf("非递归中序遍历:\n");
inOrder01(&t1);
printf("\n");
printf("非递归后序遍历:\n");
postOrder01(&t1);
printf("\n");
}
    printf("hello...\n");
system("pause");
return;
}