#include<stdio.h>
#include<stdlib.h>
#define Null 0
#define overflow   0
#define  ok        1
typedef struct BitNode
{
    int data;
    struct BitNode  *lchild, *rchild;
}BitNode,*Bitree;
int createBitree(Bitree T)
{   int *ch;
    printf("请输入你想输入的数");
    scanf("%d\n",&ch);
    if(*ch==' ')  T=Null;
    else
    {
        if(!(T=(BitNode*)malloc(sizeof(BitNode))))
            exit(overflow);
        T->data=*ch;
        createBitree(T->lchild);
        createBitree(T->rchild);
    }
    return ok;
}
int main()
{ Bitree  T;
  createBitree(T);
  if(T->data!=Null)
  printf("%d\n",T->data);
  return ok;
}
希望各位哥们帮忙调试一下并说明其中的原因，谢谢了。

#include<stdio.h>
#include<stdlib.h>
#define Null 0
#define overflow   0
#define  ok        1
typedef struct BitNode
{
    int data;
    struct BitNode  *lchild, *rchild;
}BitNode,*Bitree;
int createBitree(Bitree T)
{   int *ch;
    printf("请输入你想输入的数");
    scanf("%d\n",&ch);
    if(*ch==' ')  T=Null;
    else
    {
        if(!(T=(BitNode*)malloc(sizeof(BitNode))))
            exit(overflow);
        T->data=*ch;
        createBitree(T->lchild);
        createBitree(T->rchild);
    }
    return ok;
}
int main()
{ Bitree  T;
  createBitree(T);
  if(T->data!=Null)
  printf("%d\n",T->data);
  return ok;
}