先序遍历二叉树非递归.c

数据结构学习用到的一些程序！！里面有二叉树相关的几个

#include<stdlib.h>
#include<stdio.h>
#define M0 100                             //定义节点最大个数
#define M2 20                              //定义栈的容量
#define LEN  sizeof (BinNode)              //定义节点空间


typedef struct BinNode                     //定义节点类型
{ 
	char data;
    struct BinNode *lch,*rch;
} BinNode,*Bintree;

struct chtp   
{
	int len;      
	char ch[M0];    
};

struct BinNode *bt,*m,*stack[M2];
struct chtp s;
int top=0,i=0;

void  crt_pre(Bintree *t)                 //递归建立二叉树
{
	char c;      
	c=s.ch[i];     
	i=i+1;
    if (c=='.')  
		*t=NULL;
	else 
	{ 
		*t=(BinNode *)malloc(LEN);     
		(*t)->data=c;
		crt_pre(&(*t)->lch);	  
		crt_pre(&(*t)->rch);
	};
}


void preorder (BinNode *t)              //非递归先序遍历二叉树子函数
{
	top=0;
	while(t!=NULL||top!=0)
	{
		while(t!=NULL)
		{
			printf("%c",(*t).data);
			stack[++top]=t;
			t=t->lch;
		}
		if(top!=0)
		{
			t=stack[top--]->rch;
		}
	}
}


void main()
{
	char /*c[]={'a','b','d','.','.','.','c','e','.','.','f','.','.','!'};*/
      c[]={'a','b','c','.','.','d','e','.','g','.','.','f','.','.','.','!'};
    int i=0;
    for(i=0,s.len=0;c[i]!='!';i++,s.len++) 
		s.ch[i]=c[i];
	crt_pre(&bt);      
	preorder(bt);
	printf("\n");
}