实现二叉树各种基本运算的算法

#include<stdio.h>
#include<malloc.h>
#define MaxSize 100
typedef char ElemType;
typedef struct node
{
  ElemType data;
  struct node *lchild;
  struct node *rchild;
}BTNode;
void CreateBTree(BTNode *&b,char *str)
{
  BTNode * St[MaxSize],*p;
  int top=-1,k,j=0;char ch;
  b=NULL;
  ch=str[j];
  while(ch!='\0')
  {
    switch(ch)
    {
    case'(':top++;St[top]=p;k=1;break;
    case')':top--;break;
    case',':k=2;break;
    default:p=(BTNode *)malloc(sizeof(BTNode));
      p->data=ch;p->lchild=p->rchild=NULL;
      if(b==NULL)
        b=p;
      else
      {
        switch(k)
        {
                case 1:St[top]->lchild=p;break;
        case 2:St[top]->rchild=p;break;
        }
      }
    }
    j++;ch=str[j];
  }
}
void DestroyBTree(BTNode *&b)
{
  if(b!=NULL)
  {
    DestroyBTree(b->lchild);
        DestroyBTree(b->rchild);
    free(b);
  }
}
BTNode *FindNode(BTNode *b,ElemType x)
{
  BTNode *p;
  if(b==NULL)
    return NULL;
  else if(b->data==x)
    return b;
  else
  {
    p=FindNode(b->lchild,x);
    if(p!=NULL)
      return p;
    else
      return FindNode(b->rchild,x);
  }
}
BTNode *LchildNode(BTNode *p)
{
  return p->lchild;
}
BTNode *RchildNode(BTNode *p)
{
  return p->rchild;
}
int BTHeight(BTNode *b)
{
  int lchildh,rchildh;
  if(b==NULL)return(0);
  else
  {
    lchildh=BTHeight(b->lchild);
    rchildh=BTHeight(b->rchild);
    return(lchildh>rchildh)?(lchildh+1):(rchildh+1);
  }
}
void DispBTree(BTNode *b)
{
  if(b!=NULL)
  {
    printf("%c",b->data);
    if(b->lchild!=NULL||b->rchild!=NULL)
    {
      printf("(");
      DispBTree(b->lchild);
      if(b->rchild!=NULL)printf(",");
      DispBTree(b->rchild);
      printf(")");
    }
  }
}
int main()
{
  BTNode *b,*p,*lp,*rp;;
  printf("二叉树的基本运算如下:\n");
  printf("  (1)创建二叉树\n");
  CreateBTree(b,"A(B(D,E(H(J,k(L,M(,N))))),C(F,G(,I)))");
  printf("  (2)输出二叉树:");DispBTree(b);printf("\n");
  printf("  (3)H结点:");
  p=FindNode(b,'H');
  if(p!=NULL)
  {  lp= LchildNode(p);
     if(lp!=NULL)printf("左孩子为%c",lp->data);
     else printf("无左孩子");
     rp=RchildNode(p);
     if(rp!=NULL) printf("右孩子为%c",rp->data);
     else printf("无右孩子");
  }
  printf("\n");
  printf("  (4)二叉树b的高度:%d\n",BTHeight(b));
  printf("  (5)释放二叉树b\n");
  DestroyBTree(b);
  return 1;
}