二叉树的实现

#include <stdio.h>
#include <stdlib.h>
/*本程序作为数据结构课程（使用教材“数据结构与算法分析-C语言描述”，M. A. Ｗeiss著）关于二叉树部分的补充程序。*/ 
/*本程序使用纯 C 语言*/

typedef char ElementType;
typedef struct TreeNode {
    ElementType Element;
    struct TreeNode *Left;
    struct TreeNode *Right;
} BTNode;

BTNode *CreateTree(BTNode *root)
{
//先序递归创建二叉树，
//输入范例：abd#g##e##cf#h###
/*
       a
     /  
    /    
   b      c
  /     /
 d   e  f
        
   g      h

 */

//对应于：  a(b(d(,g),e),c(f(,h),))
    char ch;
    scanf("%c",&ch);
    if(ch=='#') {
        //printf("--%c$$$
",ch);
        return NULL;
    }
    else
    {
        //printf("++%c***
",ch);
        root=(BTNode *)malloc(sizeof(BTNode));
        root->Element=ch;
        root->Left=CreateTree(root->Left);
        root->Right=CreateTree(root->Right);
    }
    return root;
}

void PreOrder(BTNode *b)     /*先序遍历的递归算法*/
{
    if (b!=NULL) {
        printf("%c ",b->Element); /*访问根结点*/
        PreOrder(b->Left);
        PreOrder(b->Right);
    }
}

void InOrder(BTNode *b)     /*中序遍历的递归算法*/
{
    if (b!=NULL) {
        InOrder(b->Left);
        printf("%c ",b->Element); /*访问根结点*/
        InOrder(b->Right);
    }
}

void PostOrder(BTNode *b) /*后序遍历递归算法*/
{
    if (b!=NULL) {
        PostOrder(b->Left);
        PostOrder(b->Right);
        printf("%c ",b->Element); /*访问根结点*/
    }
}

int CountNode(BTNode *T) /*计算二叉树节点个数*/
{
    if ( T == NULL )
        return 0;
    else 
        return 1+CountNode(T->Left)+CountNode(T->Right);
}

int CountLeafNode(BTNode *T) /*计算二叉树叶子节点个数*/
{
    if ( T == NULL )
        return 0;
    else if ((T->Left==NULL)&&(T->Right==NULL))
        return 1;
    else 
        return CountLeafNode(T->Left)+CountLeafNode(T->Right);
}

    
int TreeDepth(BTNode *b)    /*求二叉树的深度 */
{
    int leftDep,rightDep;
    if (b==NULL) return(0); /*空树的深度为0*/
    else  
    {
        leftDep=TreeDepth(b->Left);
        /*求左子树的深度*/
        rightDep=TreeDepth(b->Right);
        /*求右子树的深度*/
        return(leftDep>rightDep)?(leftDep+1):(rightDep+1);
    }
}

BTNode *FindNode(BTNode *b,ElementType x) 
{
//在二叉树中查找值为x的结点
    BTNode *p;
    if (b==NULL)   return NULL;
    else if (b->Element==x)   return b;
    else
    {
        p=FindNode(b->Left,x);
        if (p!=NULL) return p; //判断子递归返回值
        else   return FindNode(b->Right,x);
    }
}

int Like(BTNode *b1,BTNode *b2)
{
    /*b1和b2两棵二叉树相似时返回1,否则返回0*/
    int like1,like2;
    if (b1==NULL && b2==NULL) return 1;
    else if (b1==NULL || b2==NULL)  return 0;
    else
    {
        like1=Like(b1->Left,b2->Left);
        like2=Like(b1->Right,b2->Right);
        return (like1 & like2);
        /*返回like1和like2的与*/
    }
}


/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char *argv[]) {
    BTNode *T,*p;
    T=CreateTree(p);
    PreOrder(T);
    printf("
Node:%i
",CountNode(T));
    printf("LeafNode:%i
",CountLeafNode(T));
    printf("Depth:%i
",TreeDepth(T));
    
    BTNode *f=FindNode(T,'c');
    PreOrder(f);
    
    return 0;
}