三十三.二叉树的创建、后序遍历、深度统计。

#include<stdio.h>
#include<malloc.h>
typedef struct tree{
         struct tree * lchild;
         struct tree * rchild;
         char data;
}tree;
void qianxu(tree*t)
{
         if(t)
         {
                   printf("%c",t->data);
                   qianxu(t->lchild );
                   qianxu(t->rchild );
         }
}
void zhongxu(tree * t)
{
         if(t)
         {
                   zhongxu(t->lchild);
                   printf("%c",t->data);
                   zhongxu(t->rchild);
         }
}
void houxu(tree * t)
{
         if(t)
         {
                  houxu(t->lchild);
                  houxu(t->rchild);
                  printf("%c",t->data);				              		
         }

}
int count(tree *t)
{
      int n;
      if(t==NULL)
      return 0;
      else
      n=1+count(t->lchild)+count(t->rchild);
      return n;
}
tree * copy (tree *t)
{
         tree * t1;       
         if(t==NULL)
                   t1=NULL;
         else
         {
                   t1=(tree *)malloc(sizeof(tree));                 
                   t1->data =t->data ;
                   t1->lchild =copy(t->lchild );
                   t1->rchild =copy(t->rchild );
         }
           return t1;
}
tree * createTree()
{
         char ch;
         tree * t;
         scanf("%c",&ch);
         getchar();
         if(ch=='#')
         {
                   return NULL;
         }
         else
         {                 
               t=(tree *)malloc(sizeof(tree));   
                   t->data=ch;
                   printf("请输入%c的左子树的根结点：",ch);
                   t->lchild =createTree();
                   printf("请输入%c的右子树的根结点：",ch);
        t->rchild =createTree();
         return t;
         }
}
int depth(tree *t)
{
         int m,n;//m:左子树的深度,n：右子树的深度
         if(t==NULL)
                   return 0;
         else
         {
                  m=depth(t->lchild );
                   n=depth(t->rchild );
                   if(m>n)
                       return m+1;
                   else
                       return n+1;
         }
}       

main()
{        tree * t;

tree *t1;
int n; //二叉树的结点总数
int d;//二叉树的深度
printf("空结点即用“#”表示\n");
printf("请输入二叉树的根结点：");
         t=createTree();
         printf("\n");
         printf("该二叉树的前序遍历:");
         qianxu(t);
                   printf("\n");
         printf("该二叉树的中序遍历:");
         zhongxu(t);
                   printf("\n");
         printf("该二叉树的后序遍历:");
         houxu(t);
                   printf("\n");
                   printf("该二叉树的结点总数是:");
         n=count(t);
         printf("%d",n);
                   printf("\n");
         printf("该二叉树的深度是:");
         d=depth(t);
         printf("%d",n);
                   printf("\n");
printf("复制二叉树:");
t1=copy(t);
printf("新二叉树的后序遍历是:");
qianxu(t1);
printf("\n");                 
}