c语言实现二叉树的基本操作

#include<stdlib.h>
//二叉树的节点定义
typedef struct TreeNode
{
    char ch;                  //数据域
    struct TreeNode *lchild;  //左孩子
    struct TreeNode *rchild;  //右孩子
}BTNode,*PBTNode;

//先序构造二叉树
void createBTree(PBTNode *root)
{
    char ch;
    ch=getchar();
    if(ch=='#')
        *root=NULL;
    else{
        *root=(PBTNode)malloc(sizeof(BTNode));
        (*root)->ch=ch;
        (*root)->lchild=NULL;
        (*root)->rchild=NULL;
        createBTree(&(*root)->lchild);
        createBTree(&(*root)->rchild);
    }
}

//先序遍历二叉树
void preOrder(PBTNode root)
{
    if(root==NULL)
        return;
    printf("%-3c",root->ch);
    preOrder(root->lchild);
    preOrder(root->rchild);
}

//中序遍历二叉树
void inOrder(PBTNode root)
{
    if(root==NULL)
        return;
    preOrder(root->lchild);
    printf("%-3c",root->ch);
    preOrder(root->rchild);
}

//后序遍历二叉树
void postOrder(PBTNode root)
{
    if(root==NULL)
        return;
    preOrder(root->lchild);
    preOrder(root->rchild);
    printf("%-3c",root->ch);
}

//输出叶子结点
void displyLeaf(PBTNode root)
{
    if(root==NULL)
        return;
    if(root->lchild==NULL&&root->rchild==NULL)
        printf("%-3c",root->ch);
    else{
        displyLeaf(root->lchild);
        displyLeaf(root->rchild);
    }
}

//左结点插入
void inseartLeftNode(PBTNode root,char ch)
{
    PBTNode p,newNode;
    if(root==NULL)
        return;
    p=root->lchild;
    newNode=(PBTNode)malloc(sizeof(BTNode));
    newNode->ch=ch;
    newNode->rchild=NULL;
    newNode->lchild=p;
    root->lchild=newNode;
}

//右结点插入
void inseartRightNode(PBTNode root,char ch)
{
    PBTNode p,newNode;
    if(root==NULL)
        return;
    p=root->rchild;
    newNode=(PBTNode)malloc(sizeof(BTNode));
    newNode->ch=ch;
    newNode->lchild=NULL;
    newNode->rchild=p;
    root->rchild=newNode;
}

//销毁一颗二叉树
void clear(PBTNode* root)
{
    PBTNode pl,pr;
    if(*root==NULL)
        return;
    pl=(*root)->lchild;
    pr=(*root)->rchild;
    (*root)->lchild=NULL;
    (*root)->rchild=NULL;
    free((*root));
    *root=NULL;
    clear(&pl);
    clear(&pr);
}

//删除左子树
void deleteLeftTree(PBTNode root)
{
    if(root==NULL)
        return;
    clear(&root->lchild);
    root->lchild=NULL;
}

//删除右子树
void deleteRightTree(PBTNode root)
{
    if(root==NULL)
        return;
    clear(&root->rchild);
    root->rchild=NULL;
}

//查找结点
PBTNode   search(PBTNode root,char ch)
{
    PBTNode p;
    if(root==NULL)
        return NULL;
    if(root->ch==ch)
        return root;
    else{
        if((p=search(root->lchild,ch))!=NULL)
            return p;
        else
            return  search(root->rchild,ch);
    }
}

//求二叉树的高度
int BTreeHeight(PBTNode root)
{
    int lchildHeight,rchildHeight;
    if(root==NULL)
        return 0;
    lchildHeight=BTreeHeight(root->lchild);
    rchildHeight=BTreeHeight(root->rchild);
    return (lchildHeight>rchildHeight)?(1+lchildHeight):(1+rchildHeight);
}

//求叶子结点的个数
int countLeaf(PBTNode root)
{
    if(root==NULL)
        return 0;
    if(root->lchild==NULL&&root->rchild==NULL)
        return 1;
    else{
        return countLeaf(root->lchild)+countLeaf(root->rchild);
    }
}

//求所有结点的个数
int countAll(PBTNode root)
{
    if(root==NULL)
        return 0;
    return countAll(root->lchild)+countAll(root->rchild)+1;
}

//复制二叉树
PBTNode copyBTree(PBTNode root)
{
    PBTNode p,lchild,rchild;
    if(root==NULL)
        return NULL;
    lchild=copyBTree(root->lchild);
    rchild=copyBTree(root->rchild);
    p=(PBTNode)malloc(sizeof(BTNode));
    p->ch=root->ch;
    p->lchild=lchild;
    p->rchild=rchild;
    return p;
}