#include<stdio.h>
#include<stdlib.h>
typedef struct node
{
	char data;
	struct node *lchild,*rchild;
}bintnode;
typedef struct stack
{
    bintnode *data[100];
    int tag[100];
    int top;
}seqstack;
void push(seqstack *s,bintnode *t)
{
    s->data[s->top]=t;
    s->top++;
}
bintnode *pop(seqstack *s)
{
    if(s->top!=0)
    {
        s->top--;
        return (s->data[s->top]);
    }
    else
    {
        return NULL;
    }
}
int d=0;
bintnode *createtree()/*按照前序遍歷建立一個二叉樹*/
{
	char ch;
	bintnode *t;
	if((ch=getchar())==' ')
	   t=NULL;
	else
	   {
		  t=(bintnode*)malloc(sizeof(bintnode));
		  t->data=ch;
		  t->lchild=createtree();
		  t->rchild=createtree();
 	   }
	return t;
}
void compute(bintnode *t)/*前序遍歷計算葉子節點個數*/
{
	if(t)
	{
		if(t->lchild==NULL&&t->rchild==NULL)
			d++;
		compute(t->lchild);
		compute(t->rchild);
	}
}
void ino1(bintnode *t)/*中序遍歷*/
{
	if(t)
	{
		ino1(t->lchild);
		printf("%c ",t->data);
		ino1(t->rchild);
	}
}
void pos1(bintnode *t)
{
	if(t)
	{
		pos1(t->lchild);
		pos1(t->rchild);
		printf("%c ",t->data);
	}
}
void pre1(bintnode *t)
{
	if(t)
	{
		printf("%c ",t->data);
		pre1(t->lchild);
		pre1(t->rchild);
	}
}
//--------------------------------------------------
void pre2(bintnode *t)//前序遍歷
{
    seqstack s;
    s.top=0;
    while((t)||(s.top)!=0)
    {
        if(t)
        {
            printf("%c ",t->data);
            push(&s,t);
            t=t->lchild;
        }
        else
        {
            t=pop(&s);
            t=t->rchild;
        }
    }
}
void ino2(bintnode *t)//中序遍歷
{
    seqstack s;
    s.top=0;
    while((t!=NULL)||(s.top!=0))
    {
        if(t)
        {
            push(&s,t);
            t=t->lchild;
        }
        else
        {
            t=pop(&s);
            printf("%c ",t->data);
            t=t->rchild;
        }
    }
}
void pos2(bintnode *t)//後序遍歷
{
    seqstack s;
    s.top=0;
    while((t)||(s.top!=0))
    {
        if(t)
        {
            s.data[s.top]=t;
            s.tag[s.top]=0;
            s.top++;
            t=t->lchild;
        }
        else if(s.tag[s.top-1]==1)
        {
            s.top--;
            t=s.data[s.top];
            printf("%c ",t->data);
            t=NULL;
        }
        else
        {
            t=s.data[s.top-1];
            s.tag[s.top-1]=1;
            t=t->rchild;
        }
    }
}
int main()
{
	bintnode *t;
    t=(bintnode*)malloc(sizeof(bintnode));
    printf("請建立二叉樹：");
    t=createtree();
    printf("\n葉子節點個數：");
	compute(t);
    printf("%d",d);
	printf("\n------------------------------\n");
	printf("\n遞迴");
	printf("\n前序遍歷：");
	pre1(t);
    printf("\n中序遍歷：");
    ino1(t);
    printf("\n後序遍歷：");
    pos1(t);
	printf("\n-----------------------------\n");
	printf("非遞迴");
	printf("\n前序遍歷：");
	pre2(t);
	printf("\n中序遍歷：");
    ino2(t);
    printf("\n後序遍歷：");
    pos2(t);
	printf("\n");
    return 0;
}