二叉树

树和二叉树应该是考研中比较重要的考点，这里的代码仅供自己参考！！！

/**
 *	作者:LinX  2017-6-29 - 2017-7-1
 *			
 *	内容: 二叉树的结构及其操作
 * 
 */
 
 #include <stdio.h>
 #include <stdlib.h>
 
 #define MAXSIZE 100
 
 typedef char ElemType;
 
 typedef struct BTNode
 {
 	
 	ElemType data;
 	
 	struct BTNode *lChild;
 	
 	struct BTNode *rChild;
 	
 }BTNode,BTree;
 
 BTree* createBTree(); 					//创建二叉树 
 
 void preOrder(BTree *bt);				//递归方法先序遍历 
 	
 void inOrder(BTree *bt);				//递归方法中序遍历 
 
 void postOrder(BTree *bt);				//递归方法后序遍历
 
 void preorderNonRecursion(BTree *bt);  //非递归方法先序遍历 
 
 void inorderNonRecursion(BTree *bt);   //非递归方法中序遍历
 
 void postorderNonRecursion(BTree *bt); //非递归方法后序遍历
 
 int leavesCount(BTree *bt);			//求叶子结点数目
 
 int depthCount(BTree *bt);				//求二叉树深度 
 
 int main()
 {
 	int depth,nums=0;
 	
 	BTree *bt=createBTree();
 	
	printf("先序遍历:");
 	preorderNonRecursion(bt);
 	printf("\n");
 	
 	printf("中序遍历:");
 	inorderNonRecursion(bt);
 	printf("\n");
 	
 	printf("后序遍历:");
	postorderNonRecursion(bt);
 /*	//先序遍历 
 	preOrder(bt);
 	
 	printf("\n");
 	
 	//中序遍历
	inOrder(bt);
	
	printf("\n");
	
	//后序遍历
	postOrder(bt);
	
	//二叉树深度 
	depth=depthCount(bt);
	
	printf("\n%d\n",depth);
	
	//求叶子结点的数目 
	printf("%d",leavesCount(bt));*/ 
	
 	return 0;
 }
 
 /*非递归方法中序遍历*/
 void inorderNonRecursion(BTree *bt)
 {
 	
 	BTNode *stack[MAXSIZE],*p;
 	
 	int top=-1;
 	
	p=bt;
	
 	while(top!=-1||p!=NULL)
	{
		
		while(p!=NULL)
		{
			
			stack[++top]=p;
			p=p->lChild;
			
		}
		if(top!=-1)
		{
			p=stack[top--];
			
			printf("%c ",p->data);
			
			p=p->rChild;
	
		}
			
	}
 }
 
 /*非递归方法先序遍历:先将根节点入栈，出栈，再将右孩子，左孩子入栈，再将左孩子出栈
   出栈的同时将右孩子，左孩子入栈，以此类推，直到栈空*/
 
 void preorderNonRecursion(BTree *bt)
 {
 	
	BTNode *stack[MAXSIZE],*p;
 	
	int top=-1;
		
	stack[++top]=bt;
 	
 	while(top!=-1)
 	{
 		
 		p=stack[top--];
 		
 		printf("%c ",p->data);
 		
 		if(p->rChild!=NULL)
 		{
 			
 			stack[++top]=p->rChild;	
 			
 		}
 		
 		if(p->lChild!=NULL)
 		{
 			
 			stack[++top]=p->lChild;
 			
 		}
 	}
 }
 
 /*非递归方法后序遍历*/
 
 void postorderNonRecursion(BTree *bt)
 {
 	
 	BTNode *p;
 	
 	BTNode* stack1[MAXSIZE];
	int top1=-1;
	 		 
 	BTNode* stack2[MAXSIZE];
	int top2=-1;
	
	stack1[++top1]=bt;
	
	while(top1!=-1)
	{
	
		p=stack1[top1--];
		
		stack2[++top2]=p;
		
		printf("%c ",p->data);
		
		if(p->lChild!=NULL)
		{
			
			stack1[++top1]=p->lChild;
			
		}
		
		if(p->rChild!=NULL)
		{
			
			stack1[++top1]=p->rChild;
			
		}
	}
	
	while(top2!=-1)
	{
		
		printf("%c ",stack2[top2--]->data);
		
	} 		
 } 
 
 /*求叶子结点的数目*/
 
 int nums=0;
 
 int leavesCount(BTree *bt)
 {
 	if(bt!=NULL)
 	{
 		
 		if(bt->lChild==NULL&&bt->rChild==NULL)
 		{
 			
 			return ++nums;
 			
 		}
 		
 		else
 		{
 			
 			leavesCount(bt->lChild);
 			
 			leavesCount(bt->rChild);
 		}
 	}
 } 
 
 /*求二叉树深度*/
 int depthCount(BTree *bt)
 {
	int left,right;
	
	if(bt==NULL)
	{
		return 0;
	}
	
	left=depthCount(bt->lChild)+1;
	
	right=depthCount(bt->rChild)+1;
	
	return (left>right)?left:right;
	
	//简便写法 
	
	//return depthCount(bt->lChild)+1>depthCount(bt->rChild)+1?depthCount(bt->lChild)+1:depthCount(bt->rChild)+1;
 } 
 
 
 /*先序遍历*/ 
 
 void preOrder(BTree *bt)
 {
 	
 	if(bt!=NULL)
 	{
 		
 		printf("%c ",bt->data);
 		
 		preOrder(bt->lChild);
 		
 		preOrder(bt->rChild);
 		
 	}
 }
 
 /*中序遍历*/ 
 void inOrder(BTree *bt)
 {
 	
 	if(bt!=NULL)
 	{
 		
 		inOrder(bt->lChild);
 		
 		printf("%c ",bt->data);
 		
 		inOrder(bt->rChild);
 	}
 }
 
 /*后序遍历*/  
 void postOrder(BTree *bt)
 {
 	
 	if(bt!=NULL)
 	{
 		
 		postOrder(bt->lChild);
 		
 		postOrder(bt->rChild);
 		
 		printf("%c ",bt->data);
 	}
 }
 
 /*创建二叉树 */ 
 
 BTree* createBTree()
 {
 	
 	BTNode *btn;
 	
 	ElemType c;
	
	scanf("%c",&c);
	
	if(c=='#')
	{
		btn=NULL;
	}
	
 	else
 	{
 		
 		btn=(BTNode *)malloc(sizeof(BTNode));	
 		
 		btn->data=c;
 		
 		btn->lChild=createBTree();
 		
 		btn->rChild=createBTree();
 		
 	}
 	
 	return btn;
 }