#include<iostream>
#include<stdlib.h>

using namespace std;

typedef struct BTNode BTNode;

struct BTNode{ 
    int ch;
    BTNode * left;
    BTNode * right;
};
// 建立一個二叉樹 先序輸入 0表示NULL 
BTNode * creatBTNode(){
    BTNode * p;
    int ch;
    cin>>ch;

    if(ch ==0){
        p=NULL;
    }
    else
 
{
        p=(BTNode *)malloc(sizeof(BTNode));
        p->ch=ch;
        p->left=creatBTNode();
        p->right=creatBTNode();
    }
    return p;
}

//*****************先序遍歷************
void  preOrderTraverse(BTNode * node){
    if(node){
        cout<<node->ch<<' ';
        preOrderTraverse(node->left);
        preOrderTraverse(node->right); 
    }
}

//******************中序遍歷**********
 

void inOrderTraverse(BTNode * node){
    if(node){
        inOrderTraverse(node->left);
        cout<<node->ch<<' ';
        inOrderTraverse(node->right);
    }
}

//*****************後序遍歷輸出*******
void lastOrderTraverse(BTNode * node){
    if(node){
        lastOrderTraverse(node->left);
        lastOrderTraverse(node->right);
        cout
 
<<node->ch<<' ';
    }
}
//****************二叉樹節點數目******
int  NodeNum(BTNode * node){
    if(node==NULL){
        return 0;
    }
    else{
        return 1+NodeNum(node->left)+NodeNum(node->right);  
    } 
}
//*************二叉樹深度*************
int DepthOfTree(BTNode * node){
    if(node){
        return DepthOfTree(node->left)>DepthOfTree(node->right)?DepthOfTree(node->left)+1:DepthOfTree(node->right)+1;
    }
    if(node==NULL){
        return 0;
    }
}
//**************二叉樹葉子節點數*******
int leafNum(BTNode * node){
    if(!node){
        return 0;
    }
    else if(node->left==NULL&&node->right==NULL){
        return 1;
    }
    else{
        return (leafNum(node->left)+leafNum(node->right));
    }
}


int main(){

    BTNode * bttree=creatBTNode();

    cout<<"先序遍歷輸出："<<endl;
    preOrderTraverse(bttree);

    cout<<"\n中序遍歷輸出："<<endl;
    inOrderTraverse(bttree);

    cout<<"\n後序遍歷輸出："<<endl;
    lastOrderTraverse(bttree);

    cout<<"\n二叉樹節點數目："<<endl;
    cout<<NodeNum(bttree)<<endl;

    cout<<"二叉樹深度"<<endl;
    cout<<DepthOfTree(bttree)<<endl;

    cout<<"葉子節點數"<<endl;
    cout<<leafNum(bttree)<<endl;

    return 0;
}

原文:http://blog.csdn.net/ricardo_he/article/details/41119709