利用迴圈佇列層次遍歷一棵二叉樹 遞迴實現

程式碼實現：

#include <iostream> ///迴圈佇列實現層次遍歷二叉樹
#include <stdio.h>
#include <stdlib.h>

#define Maxsize 100
#define OK 1
#define OVERFLOW -2

using namespace std;

typedef char CElemType;

typedef struct BiNode
{
    CElemType data;
    struct BiNode*lchild,*rchild;
} BiNode,*BiTree;

typedef BiTree ElemType; ///存放二叉樹地址的迴圈佇列 吧

typedef struct
{
    ElemType *base;
    int front;
    int rear;
} SeqQueue;

int InitQueue(SeqQueue &Q)
{
    Q.base=(ElemType *)malloc(Maxsize*sizeof(ElemType));
    if(!Q.base)
        exit(OVERFLOW);
    Q.front = Q.rear =0;
    return OK;
}

int EnQueue(SeqQueue &Q,ElemType e)
{
    if((Q.rear+1)%Maxsize==Q.front)
    {
        cout<<"Queue Full"<<endl;
        return 0;
    }
    Q.rear = (Q.rear+1)%Maxsize;
    Q.base[Q.rear]=e;
    return 1;
}

int DeleQueue(SeqQueue &Q,ElemType &e)
{
    if(Q.front==Q.rear)
    {
        cout<<"Queue Empty"<<endl;
        return 0;
    }
    Q.front=(Q.front+1)%Maxsize;
    e=Q.base[Q.front];
    return 1;
}

int Empty(SeqQueue Q)
{
    if(Q.rear==Q.front)
        return 1;
    else return 0;
}

void CreateBiTree2(BiTree &t)  ///引用實現建立一棵二叉樹
{
    char ch;
    scanf("%c",&ch);
    if(ch==' ')
        t=NULL;
    else
    {
        t=(BiTree)malloc(sizeof(BiNode));
        t->data=ch;
        CreateBiTree2(t->lchild);
        CreateBiTree2(t->rchild);
    }
}

void Cengci(BiTree t)
{
    BiTree p=t;
    SeqQueue Q;
    int flag=InitQueue(Q);
    EnQueue(Q,p);
    while(!Empty(Q))
    {
        DeleQueue(Q,p);
        cout<<p->data<<" ";
        if(p->lchild)
            EnQueue(Q,p->lchild);
        if(p->rchild)
            EnQueue(Q,p->rchild);
    }
}

int main()
{
    BiTree T;
    cout<<"Please Input One BiTree :"<<endl;
    CreateBiTree2(T);
    cout<<"Cengci Order Output :"<<endl;
    Cengci(T);
    return 0;
}