我剛好有個擴充套件先序輸入，然後凹入法輸出的原始碼，你改改就行了：

#include "stdio.h"

#include "malloc.h"

typedef struct Node

{

char name;

struct Node *LChild;

struct Node *RChild;

}BiTNode,*BiTree;

void CreateBiTree(BiTree *bt)

{

char ch;

ch=getchar();

if(ch==".")(*bt)=NULL;

else

{

*bt=(BiTree)malloc(sizeof(BiTNode));

(*bt)->name=ch;

CreateBiTree(&(*bt)->LChild);

CreateBiTree(&(*bt)->RChild);

}

}

void PrintTree( BiTree T, int i )

{

if(T)

{

int j;

for( j=i; j>0; j--)

printf(" ");

printf("%c\n", T->name);

PrintTree( T->LChild, i+1 );

PrintTree( T->RChild, i+1 );

}

}

void main ()

{

BiTree *T;

CreateBiTree(T);

PrintTree(*T,0);

}