(C语言)二叉树非递归遍历前序和中序(数据结构十四)

1.数据类型定义

在代码中为了清楚的表示一些错误和函数运行状态，我们预先定义一些变量来表示这些状态。在head.h头文件中有如下定义：

//定义数据结构中要用到的一些变量和类型
#ifndef HEAD_H
#define HEAD_H

#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#include <math.h>

#define TRUE  1
#define FALSE 0
#define OK    1
#define ERROR  0
#define INFEASIBLE -1
#define OVERFLOW   -2    //分配内存出错

typedef int  Status;     //函数返回值类型
typedef int  ElemType;   //用户定义的数据类型

#endif

2.遍历过程中用到的栈结构代码如下

LinearStack.h中

#ifndef LINEAR_STACK
#define LINEAR_STACK
#include "head.h"

#define  STACK_INIT_SIZE 100  
#define  STACK_INCREMENT 10    


typedef pBiNode Type;


typedef struct Stack{
	Type *base;   //栈底
	Type *top;    //栈顶
	int     size;    //栈大小
}Stack,*pStack;





//初始化栈
Status InitStack(pStack &S){
	S=(pStack)malloc(sizeof(Stack));
	Type* p=(Type*)malloc(STACK_INIT_SIZE*sizeof(Type));
	if(!p) return OVERFLOW;
	S->base=p;
	S->top=p;
	S->size=STACK_INIT_SIZE;
	return OK;
}

Status freeStack(pStack &S){
	free(S);
	S=NULL;
	return OK;
}
//销毁栈
Status DestroyStack(pStack &S){
	free(S->base);
	S->base=NULL;
	S->top=NULL;
	freeStack(S);
	return OK;
}
//清空栈
Status ClearStack(pStack &S){
	S->top=S->base;
	return OK;
}
//栈是否为空
Status StackEmpty(pStack S){
	return S->top==S->base;
}
//栈长度
int StackLength(pStack S){
	return S->top-S->base;
}
//得到栈顶数据级e
Status GetTop(pStack S,Type &e){
	e=*(S->top-1);
	return OK;
}
//入栈
Status Push(pStack &S,Type e){
	if(StackLength(S)>=S->size)
		S->base=(Type*)realloc(S->base,(S->size+STACK_INCREMENT)*sizeof(Type));
	if(!S->base) return OVERFLOW;
	S->top=S->base+StackLength(S);
	S->size+=STACK_INCREMENT;
	*S->top++=e;
	return OK;
}
//出栈
Status Pop(pStack &S,Type &e){
	if(StackLength(S)<1) return ERROR;
		e=*--S->top;
	return OK;
}

// Status print(Type e){
// 	printf("%d ",e);
// 	return OK;
// }

//用vistit遍历栈
Status StackTraverse(pStack S,Status(*visit)(Type)){
	while (S->top>S->base)
		(*visit)(*--S->top);
	return OK;
}
// Status printStack(pStack S){
// 	StackTraverse(S,print);
// 	return OK;
// }



#endif

3.二叉树结构代码如下

#ifndef BITREE_H
#define BITREE_H

#include "head.h"


typedef struct BiNode{
	ElemType data;
	struct BiNode *left,*right;
}BiNode,*pBiNode;


Status InsertRight(pBiNode &root,ElemType e);
Status InsertLeft(pBiNode &root,ElemType e);


Status InitBiTree(pBiNode &tree){
	tree=(pBiNode)malloc(sizeof(BiNode));
	if(!tree) return OVERFLOW;
	tree->data=-999999;
	tree->left=NULL;
	tree->right=NULL;
	return OK;
}
Status BiTreeEmpty(pBiNode root){
	if(root==NULL) return ERROR;
	return root->left==root->right && root->data==-999999;
}

Status HasNoNode(pBiNode root){
	if(root==NULL) return ERROR;
	return root->left==root->right ;
}

Status CreatTreeNode(pBiNode &node,ElemType e){
	node=(pBiNode)malloc(sizeof(BiNode));
	if(!node) return OVERFLOW;
	node->data=e;
	node->left=NULL;
	node->right=NULL;
	return OK;
}
Status InsertRight(pBiNode &root,ElemType e){
	if(root->right==NULL){
		if(e>root->data){
			pBiNode p;
			CreatTreeNode(p,e);
			root->right=p;
			return OK;
		}else{
			pBiNode p;
			CreatTreeNode(p,e);
			root->left=p;
			return OK;
		}

	}else{
		e>root->data? InsertRight(root->right,e):InsertLeft(root,e);
	}

}
Status InsertLeft(pBiNode &root,ElemType e){
	if(root->left==NULL){
		if(e>root->data){
			pBiNode p;
			CreatTreeNode(p,e);
			root->right=p;
			return OK;
		}else{
			pBiNode p;
			CreatTreeNode(p,e);
			root->left=p;
			return OK;
		}

	}else{
		e<=root->data?InsertLeft(root->left,e):InsertRight(root,e);
	}

}


Status InsertTree(pBiNode &root,ElemType e){
	if(BiTreeEmpty(root)){
		root->data=e;
		return true;
	}
	if(e>root->data){
		InsertRight(root,e);
	}else{
		InsertLeft(root,e);
	}
}


Status CreateBiTree(pBiNode &root,ElemType *a,int n){
	for (int i=0;i<n;i++)
	{
		InsertTree(root,a[i]);
	}
	return true;
}
 Status print(ElemType e ){
 	printf("%d ",e);
 	return true;
 }

Status PreOrderTraverse(pBiNode root,Status(*p)(int)){
	if(root){
		(*p)(root->data);
		PreOrderTraverse(root->left,p);
		PreOrderTraverse(root->right,p);
	}
	return OK;
}

Status MiddleOrderTraverse(pBiNode root,Status(*p)(int)){
	if(root){
		MiddleOrderTraverse(root->left,p);
		(*p)(root->data);
		MiddleOrderTraverse(root->right,p);
	}
	return OK;
}

Status AfterOrderTraverse(pBiNode root,Status(*p)(int)){
	if(root){
		AfterOrderTraverse(root->left,p);
		AfterOrderTraverse(root->right,p);
		(*p)(root->data);
	}
	return OK;
}

Status ClearBiTree(pBiNode &root){
	if(root){
		ClearBiTree(root->left);
		ClearBiTree(root->right);
		free(root);
		root==NULL;
	}
	return OK;
}


#endif

4.遍历测试如下

#include "BiTree.h"

#include "LinearStack.h"

//非递归中序
void MiddleTraverse(pBiNode Root){
	pStack S;
	InitStack(S);
	pBiNode p=Root;
	while(p||!StackEmpty(S)){
		if(p){
			Push(S,p);
			p=p->left;
		}else{
			Pop(S,p);
			printf("%d ",p->data);
			p=p->right;
		}
	}
}

//非递归前序
void PerTraverse(pBiNode Root){
	pStack S;
	InitStack(S);
	pBiNode p=Root;
	while(p||!StackEmpty(S)){
		if(p){
			printf("%d ",p->data);
			Push(S,p);
			p=p->left;
		}else{
			Pop(S,p);
			p=p->right;
		}
	}
}



void main(){
	ElemType a[14]={100,50,200,40,30,45,60,55,61,200,150,300,250,400};
	pBiNode root;
	InitBiTree(root);
	CreateBiTree(root,a,14);

	printf("前序：");
	PreOrderTraverse(root,print);

	printf("\n中序：");
	MiddleOrderTraverse(root,print);

	printf("\n后序：");
	AfterOrderTraverse(root,print);


	printf("\n非递归前序：");
	PerTraverse(root);

	printf("\n非递归中序：");
	MiddleTraverse(root);


	ClearBiTree(root);

}

5.插入的二叉树

6.遍历结果 

前序：100 50 40 30 45 60 55 61 200 150 300 250 400
中序：30 40 45 50 55 60 61 100 150 200 250 300 400
后序：30 45 40 55 61 60 50 150 250 400 300 200 100
非递归前序：100 50 40 30 45 60 55 61 200 150 300 250 400
非递归中序：30 40 45 50 55 60 61 100 150 200 250 300 400