链式二叉树遍历具体程序演示

二叉树操作
                遍历

                      先序遍历【先访问根节点】
                              先访问根节点
                              再先序访问左子树
                              再先序访问右子树

                      中序遍历【中间访问根节点】
                              中序遍历左子树
                              再访问根节点
                              再中序遍历右子树

                      后序遍历【最后访问根节点】
                              先后序遍历左子树
                              再后序遍历右子树
                              再访问根节点

链式二叉树.cpp
--------------------------------------
#include <stdio.h>
#include <malloc.h>
typedef struct BTNode
{
     char data;
     struct BTNode * pLchild;
     struct BTNode * pRchild;
}BTNode;

BTNode * CreateBTree(void);
void PreTraverseBTree(BTNode *);
void InTraverseBTree(BTNode *);
void PostTraverseBTree(BTNode *);
int main()
{
    BTNode * pT = CreateBTree();
    //PreTraverseBTree(pT);
    //InTraverseBTree(pT);
    PostTraverseBTree(pT);

    return 0;
}

BTNode * CreateBTree(void)
{
   BTNode * pA = (BTNode *)malloc(sizeof(BTNode));
   BTNode * pB = (BTNode *)malloc(sizeof(BTNode));
   BTNode * pC = (BTNode *)malloc(sizeof(BTNode));
   BTNode * pD = (BTNode *)malloc(sizeof(BTNode));
   BTNode * pE = (BTNode *)malloc(sizeof(BTNode));

   pA->data = 'A';
   pB->data = 'B';
   pC->data = 'C';
   pD->data = 'D';
   pE->data = 'E';

   pA->pLchild = pB;
   pA->pRchild = pC;
   pB->pLchild = pB->pRchild = NULL;
   pC->pLchild = pD;
   pC->pRchild =NULL;
   pD->pLchild =NULL;
   pD->pRchild =pE;
   pE->pLchild = pE->pRchild = NULL;

   return pA;
}

void PreTraverseBTree(BTNode * pT)
{
     if (NULL!=pT)
     {
         printf("%c\n",pT->data);

     if (NULL!=pT->pLchild)
         {
         PreTraverseBTree(pT->pLchild); //pLchild代表整个左子树
         }
     if (NULL!=pT->pRchild)
         {
         PreTraverseBTree(pT->pRchild);
         }
     }
}

void InTraverseBTree(BTNode * pT)
{
    if (NULL!=pT)
    {
     if (NULL!=pT->pLchild)
     {
         InTraverseBTree(pT->pLchild); //pLchild代表整个左子树
     }

     printf("%c\n",pT->data);

     if (NULL!=pT->pRchild)
     {
         InTraverseBTree(pT->pRchild);
     }
    }
}

void PostTraverseBTree(BTNode * pT)
{
    if (NULL!=pT)
    {
     if (NULL!=pT->pLchild)
     {
         PostTraverseBTree(pT->pLchild); //pLchild代表整个左子树
     }

     if (NULL!=pT->pRchild)
     {
        PostTraverseBTree(pT->pRchild);
     }
     printf("%c\n",pT->data);
    }
}