四叉树的前序，后序，层次遍历

 

//四叉树的前序，后序，层次遍历
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
using namespace std;
typedef char datatype;

typedef struct node        //二叉树
{
 datatype data;
 struct node *lt,*rt,*lb,*rb;
} fourtnode, *fourtree;

typedef struct stack
{
fourtree data[100];
 int tag[100];
 int top; 
} seqstack;

 

//队列的顺序结构
#define MAXQSIZE 100
typedef struct
{
   fourtree * base;
 int front;
    int rear;
}SqQueue;

int  InitQueue (SqQueue &Q)
{ //构造空队列
 Q.base=(fourtree*)malloc (MAXQSIZE *sizeof(fourtree));//申请连续的存储空间
 if (!Q.base) exit(0);
 Q.front=Q.rear=0;//头、尾指针的初始化
 return 1;
}
int  EnQueue (SqQueue &Q,fourtree t)
{//入队
 if ((Q.rear+1) % MAXQSIZE ==Q.front) return 0;//队满则返回出错信息
 Q.base[Q.rear]=t;//队尾插入元素
 Q.rear = (Q.rear+1)%MAXQSIZE;//队尾指针后移
 return 1;
}

int OutQueue (SqQueue &Q, fourtree & t)
{//出队
 if (Q.rear ==Q.front) return 0;//队空的话则返回出错信息
 t=Q.base[Q.front];
 Q.front  = (Q.front+1)%MAXQSIZE;//队头指针后移
 return 1;
}

void createbintree(fourtree & t)
{
 char ch;
 
 if((ch=getchar())== '#')
  t= NULL;
 else
 {
  t = (fourtree )malloc(sizeof(fourtnode));
  t->data = ch;
 
 
  createbintree(t->lb);
  createbintree(t->rb);
  createbintree(t->rt);
  createbintree(t->lt);
 }
}//CreateBiTree

void preorder(fourtree t)//递归前序遍历
{
 if(t)
 {
  cout<<t->data;
  preorder( t->lb);
  preorder( t->rb);
  preorder( t->rt );
  preorder( t->lt);
 
 
 
 }
}

void postorder(fourtree t)//递归后序遍历
{
 if(t)
 {
   postorder( t->lb );
   postorder( t->rb);
   postorder( t->rt);
   postorder( t->lt);
    cout<<t->data;
 }
}

void levelorder(fourtree t)
{ SqQueue Q;
 InitQueue (Q);

if(t)
{
 EnQueue (Q, t);
 while(Q.front !=Q.rear)
 {
  OutQueue (Q,  t);
  cout<<t->data;
  if(t->lb)
   EnQueue (Q, t->lb);
  if(t->rb)
   EnQueue (Q, t->rb);
  if(t->rt)
   EnQueue (Q, t->rt);
  if(t->lt)
   EnQueue (Q, t->lt);
 }
 
 
 
}

 

}
int main()               
{
 fourtree root;
 printf("请输入您要建立的二叉树的先序扩展序列(用#表示空)\n");
 createbintree(root);
 printf("构造二叉树成功!\n");
 cout<<"递归前序遍历"<<endl;
 preorder(root);
 cout<<endl;
 cout<<"递归后序遍历"<<endl;
 postorder(root );
 cout<<endl;
 cout<<"层次遍历"<<endl;
 levelorder( root);
 cout<<endl;
 return 0;
}