按照教材中关于二叉树的抽象数据类型定义，采用二叉链表存储结构，编程实现二叉树的各种基本操作，并通过主函数调用，简单测试各基本函数的正确性。 比如：二叉树的基本操作可包括： (1) void InitBT( BTreeNode *&BT ) //初始化二叉树BT (2) void CreateBT( BTreeNode *&BT, char *a ) //根据字符串a所给出二叉树的描述，建立二叉链表存储结构 (3) int EmptyBT( BTreeNode *BT) //检查二叉树BT是否为空，空返回1，否则返回0 (4) int DepthBT( BTreeNode *BT) //求二叉树BT的深度并返回该值 (5) int NodeCount(BTreeNode *BT) //求二叉树BT的总结点个数 (6) void PreOrder( BTreeNode *BT) //先序遍历递归算法 (7) void InOrder( BTreeNode *BT) //中序遍历递归算法 (8) void PostOrder( BTreeNode *BT) //后序遍历递归算法 (9) int FindBT( BTreeNode *BT, ElemType x) //查找二叉树BT中值为x的结点，若查找成功返回1，否则返回0 (10)void DestroyBT( BTreeNode *&BT ) //销毁二叉树BT

以下是二叉树基本操作的代码实现：

#include <iostream>
#include <cstring>
using namespace std;

typedef char ElemType;
typedef struct BTreeNode {
    ElemType data;
    struct BTreeNode *lchild, *rchild;
} BTreeNode, *BT;

void InitBT(BT &BT) {
    BT = NULL;
}

void CreateBT(BT &BT, char *a, int &i) {
    if (a[i] == '\0') {
        return;
    }
    if (a[i] == '#') {
        BT = NULL;
    } else {
        BT = new BTreeNode;
        BT->data = a[i];
        CreateBT(BT->lchild, a, ++i);
        CreateBT(BT->rchild, a, ++i);
    }
}

int EmptyBT(BT BT) {
    return BT == NULL;
}

int DepthBT(BT BT) {
    if (BT == NULL) {
        return 0;
    }
    int left_depth = DepthBT(BT->lchild);
    int right_depth = DepthBT(BT->rchild);
    return max(left_depth, right_depth) + 1;
}

int NodeCount(BT BT) {
    if (BT == NULL) {
        return 0;
    }
    return NodeCount(BT->lchild) + NodeCount(BT->rchild) + 1;
}

void PreOrder(BT BT) {
    if (BT != NULL) {
        cout << BT->data << " ";
        PreOrder(BT->lchild);
        PreOrder(BT->rchild);
    }
}

void InOrder(BT BT) {
    if (BT != NULL) {
        InOrder(BT->lchild);
        cout << BT->data << " ";
        InOrder(BT->rchild);
    }
}

void PostOrder(BT BT) {
    if (BT != NULL) {
        PostOrder(BT->lchild);
        PostOrder(BT->rchild);
        cout << BT->data << " ";
    }
}

int FindBT(BT BT, ElemType x) {
    if (BT == NULL) {
        return 0;
    }
    if (BT->data == x) {
        return 1;
    }
    return FindBT(BT->lchild, x) || FindBT(BT->rchild, x);
}

void DestroyBT(BT &BT) {
    if (BT != NULL) {
        DestroyBT(BT->lchild);
        DestroyBT(BT->rchild);
        delete BT;
        BT = NULL;
    }
}

int main() {
    BT BT;
    InitBT(BT);

    char a[100];
    cin >> a;
    int i = 0;
    CreateBT(BT, a, i);

    cout << EmptyBT(BT) << endl;
    cout << DepthBT(BT) << endl;
    cout << NodeCount(BT) << endl;
    PreOrder(BT);
    cout << endl;
    InOrder(BT);
    cout << endl;
    PostOrder(BT);
    cout << endl;
    cout << FindBT(BT, 'E') << endl;
    DestroyBT(BT);

    return 0;
}

上述代码实现了二叉树的基本操作，可以根据输入的字符串构造二叉树，并对其进行各种操作。