#include <stdio.h>
#include <stdlib.h>
typedef struct node
{
    int num;
    struct node *left;
    struct node *right;
}Node;
/*显示*/
/*中序遍历*/
void show(Node *ptr)
{
  if(ptr!=NULL)
  {
       show(ptr->left);
      printf("[%d]",ptr->num);
      show(ptr->right);
  }
}
/*创建二叉树*/
Node *sll_insert(Node *head,int value)
{
    register Node *ptr;
    register Node *back;
    register Node *new_node;
    /*创建新内存*/
    new_node=(Node *)malloc(sizeof(Node));
    if(!new_node)
    {
        fprintf(stderr,"ERROR");
        exit(1);
    }
    new_node->num=value;
    new_node->left=NULL;
    new_node->right=NULL;
    /*树为空，返回新结点*/
    if(!head)
    {
        return new_node;
    }
    else
        ptr=head;
    while(ptr!=NULL)
    {
         back=ptr;
         /*比较元素值与节点值*/
         if(ptr->num<value)
         {
             ptr=ptr->right;/*节点大于元素值在右边*/
         }
         else
         {
             ptr=ptr->left;/*否则在左边*/
         }
    }
    if(back->num>value)
    {
        back->left=new_node;
    }
    else
    {
        back->right=new_node;
    }
    return head;
}

/*查找涵数*/
Node *find_node(Node *head,int find_num,int *ops)
{
    register Node *previous;
    register Node *ptr;
    previous=ptr;
    ptr=head;
    *ops=0;
    while(ptr!=NULL)
    {
        if(ptr->num==find_num)
        {
            return previous;
        }
        else
        previous=ptr;
        if(ptr->num>find_num)
        {
            ptr=ptr->left;
            *ops=-1;/*在左边*/
        }
        else
        {
            ptr=ptr->right;/*在右边*/
            *ops=1;
        }
    }
    return NULL;/*没有找到*/
}
/*删除*/
Node *del_delete(Node *head,int value)
{
     register Node *ptr;
     register Node *previous;
     register Node *next;
     int ops;
     previous=find_node(head,value,&ops);
     if(!previous)
         return head;
     switch(ops)
     {
     case 1:ptr=previous->right;break;/*在右边*/
     case -1:ptr=previous->left;break;
     case 0:ptr=previous;break;
     }
     if(ptr->left==NULL)/*没有左子树*/
     {
         if(ptr!=previous)/*是否结点*/
         {
             previous->right=ptr->right;
         }
         else
             head=head->right;
         free(ptr);     return head;
     }
     if(ptr->right==NULL)/*没有右子树立*/
     {
         if(ptr->right==NULL)
         {
             previous->left=ptr->left;
         }
         else
             head=head->left;
         free(ptr);
         return head;
     }
     /*有左子树，右子树结点*/
    previous=ptr;/*保存父结点*/
    next=ptr->left;
     while(next->right!=NULL)
     {
         previous=next;
         next=next->right;
     }
     ptr->num=next->num;
     if(previous->left==next)
     {
         previous->left=next->left;
     }
     else
     {
         previous->right=next->right;
     }
     free(next);
     return head;
}
/*主函数*/
int main()
{
    register Node *head=NULL;
    int num;
    int del_num;
    printf("输入值=>");
    while(1)
    {
        scanf("%d",&num);
        if(num==0)
        {
            break;
        }
        head=sll_insert(head,num);
        show(head);
        printf("\n");
    }
  printf("输入删除值==>");
  while(1)
  {
      scanf("%d",&del_num);
      if(del_num==0)
      {
          break;
      }
      head=del_delete(head,del_num);
      show(head);
      printf("\n");
  }
  return 0;
}

插入程序不能输入两个1。是什么问题？
删除不了整个树？请教一下前辈。