用C语言来写一个创建二叉树并且对其进行先根遍历的程序，为什么没有输出呢？

你在递归的时候没有设置递归的终止信派条件因此会无限递归下去，

在建树时把叶子节点的左右孩子指针赋为NULL。

然后再递归遍码坦镇历迟粗的时候

void digui(BTree bt)

{

if(bt!=NULL){

printf("%c",bt->data)

digui(bt->rchild)

digui(bt->lchild)

}

else return

}

这样就可以了

#include <stdio.h>

#include <malloc.h>

/*定义结构体*/

typedef struct BitTree {

char data

struct BitTree *lchild,*rchild

}BitNode,*BiTree

typedef int status

/*构建树*/

BiTree CreateBiTree(){

BiTree T

char ch

scanf("%c",&ch)

if(ch==' ')T=NULL

else{

T=(BitNode *)malloc(sizeof(BitNode))

T->data=ch

T->lchild=CreateBiTree( )

T->滑判rchild=CreateBiTree( )

}

return T

}

/*遍历输出，先根*/

void PreOrderTraverse(BiTree T){

if(T){

printf("%c",T->data)

PreOrderTraverse(T->lchild)

PreOrderTraverse(T->rchild)

}

}

/*遍历输出，中根*/

void InOrderTraverse(BiTree T){

if(T){

InOrderTraverse(T->橡枣lchild)

printf("%c",T->data)

InOrderTraverse(T->rchild)

}

}

/*遍历输出，后根*/

void PostOrderTraverse(BiTree T){

if(T){

PostOrderTraverse(T->lchild)

PostOrderTraverse(T->rchild)

printf("%c",T->data)

}

}

void main(){

BiTree T

printf("Please input BiTree node with InOeder:"信如改)

T=CreateBiTree()

printf("\nPreOrder is:")

PreOrderTraverse(T)

printf("\nInOeder is:")

InOrderTraverse(T)

printf("\nProstOrder is:")

PostOrderTraverse(T)

printf("\n")

}

A

(B C)

(D E) (F G)

以这课树为例

#include <stdio.h>

#include <stdlib.h>

typedef char Elem

typedef struct Node

{

Elem data

struct Node *pLchild

struct Node *pRchild

}BTreeNode, *BTree

BTree CreateBTree(BTree T, Elem *str)//创建二叉树

{

static int i = 0

if ('0' == str[i])

{

T = NULL

}

else

{

T = (BTree) malloc (sizeof(BTreeNode))

T->data = str[i++]

T->pLchild = CreateBTree(T->pLchild, str)

i++

T->pRchild = CreateBTree(T->pRchild, str)

}

return T

}

void PostTraverseBTree(BTree T)//后序

{

if (NULL != T)

{

PostTraverseBTree(T->pLchild)

PostTraverseBTree(T->pRchild)

printf("%c ", T->data)

}

}

void InTraverseBTree(BTree T)//中序

{

if (NULL != T)

{

InTraverseBTree(T->pLchild)

printf("%c ", T->data)

InTraverseBTree(T->pRchild)

}

}

void PreTraverseBTree(BTree T)//先序

{

if (NULL != T)

{

printf("%c ", T->data)

PreTraverseBTree(T->pLchild)

PreTraverseBTree(T->pRchild)

}

}

int main(void)

{

BTree T = NULL

Elem str[] = "ABD00E00CF00G00"

T = CreateBTree(T, str)

printf("\n\n")

printf("先拆返圆序遍历:\n")

PreTraverseBTree(T)

printf("\n\n")

printf("旅塌中序遍历:\n")

InTraverseBTree(T)

printf("\n\n")

printf("后序遍历:\n")

PostTraverseBTree(T)

printf("\n\n"世嫌)

}

---