ch5_7.c

清华出版社出版

void crt_bt_pre(JD *bt)
{  char ch;
   printf("ch=");
   scanf("%c",&ch);
   getchar();
   if(ch=='')  bt=NULL;
   else
   {   bt=(JD *)malloc(sizeof(JD));
       bt->data=ch;
       crt_bt_pre(bt->lchild);
       crt_bt_pre(bt->rchild);
   }
}