二叉树基本操作实现（二叉树的链式存储）

#include <iostream>
using namespace std;
typedef struct bintree_node  
{
    int data;
    bintree_node *lchild;
    bintree_node *rchild;
}bintree_node;

typedef struct stack
{
    bintree_node *data[100];
    int tag[100];//为栈中每个元素设置标记，用于后序遍历
    int top;
}seqstack;

void push(seqstack *s, bintree_node *p)
{
    s->data[++s->top] = p;
}

bintree_node *pop(seqstack *s)
{
    if(s->top != -1)
    {
        s->top--;
        return (s->data[s->top + 1]);
    }
    else
        return NULL;
}

bintree_node *bintree_create()
{
    bintree_node *p = (bintree_node *)malloc(sizeof(bintree_node));
    if(NULL == p)
    {
        cout << "alloc memory error!!!" << endl;
        return NULL;
    }
    cin >> (p->data);
    if(p->data == -1)
    {
        return NULL;
    }
    p->lchild = bintree_create();
    p->rchild = bintree_create();
    return p;
}

void prebintree(bintree_node *p)//前序遍历递归实现
{
    if(p)
    {
        cout << p->data << "\t";
        prebintree(p->lchild);
        prebintree(p->rchild);
    }
}
void prebintree1(bintree_node *p)//前序遍历非递归实现
{
    seqstack s;
    s.top = -1;
    while ((p) || (s.top != -1))
    {
        while (p)
        {
            cout << p->data << "\t";
            s.top++;
            s.data[s.top] = p;
            p = p->lchild;
        }
        if(s.top > -1)
        {
            p = pop(&s);
            p = p->rchild;
        }
    }
}
void levelTraverse(bintree_node *p)
{
    bintree_node *queue[20];              
    bintree_node *tmp;
    int front = 0, rear = 0;//表示队头指针和队尾指针
    if(p)
    {
        tmp = p;//根指针入队
        queue[rear] = tmp;
        rear = (rear + 1)%20;//队尾指针加一对20取余，可实现循环队列，合理利用空间
        while(front != rear)//队不空
        {
            tmp = queue[front];//出队，将值赋给tmp
            cout << tmp->data;
            front = (front + 1)%20;
            if(tmp -> lchild)//如果tmp有左子树，将左子树入队
            {
                queue[rear] = tmp->lchild;
                rear = (rear + 1)%20;
            }
            if(tmp->rchild)//如果tmp有右子树，将右子树入队
            {
                queue[rear] = tmp->rchild;
                rear = (rear + 1)%20;
            }
        }
    }
}
int main()
{
    bintree_node *p = bintree_create();
    prebintree1(p);
    levelTraverse(p);
    cout << endl;
    return 0;
}