BinarySortTree二叉排序树(2010年12月07日)

It is a easy algorithm to create binary sort,insert one data into the tree,and delete a data from the the tree.I am not a high person,so I hope someone could give me more and better advices to rewrite it.and I do last explain,I write these words and add note in the pragram,not as to my English is so good,Instead,my English is so poor.It is a turth that my cet-4 still doesn't passed.I just feel that we need more practices to prove our Englist especailly in the aspect of writting.

 

 

#include <iostream>
using namespace std;
typedef struct node
{
 int data;//value
 node * left;                         //left child tree
 node * right;                        //right child tree
}*Node;                                //node structure

void InsertBST(Node t,int key);
void CreateBST(Node &t,int a[],int n)                    //Create BinaryTree according to the function named InsertBST()
{
 /*

     Get the number from arrary named a[],then insert into the tree one by one

*/
 Node temp=new node;
 temp->data=a[0];
 temp->left=temp->right=NULL;     //Build a node in a[0],and have it root node of the tree
 t=temp;    //restore root node
 for(int i=1;i<n;i++)
 {
      InsertBST(t,a[i]);     //Call  InsertBST()

 }
 
}
void InsertBST(Node t,int key)
{
 Node head=t;                      //restore the head node of the tree  in case it be destory
 Node parent;
 Node temp=new node;          //Alloc one node space to resotre the key
  temp->data=key;
 temp->left=NULL;
 temp->right=NULL;

 while(head)
 {
     parent=head;
  if(key==head->data)           //If the key equals one of the array a[],insert nothing
  {

   delete temp;
   return;
  }
  else
  {
   if(key<head->data)     //If the key smaller than  the  current data ,turn to left
   {
    head=head->left;
   }
   else
   {
    head=head->right;   //If the key bigger than  the  current data ,turn to right

   }
  }
 }
 if(key<parent->data)   //If the key smaller than the parrent data,make the key node being parrent left child
 {
  parent->left=temp;
 }
 else                              //If the key smaller than the parrent data,make the key node being parrent left child
 {
  parent->right=temp;
 }

}
void DeleteBST(Node t,int key)
{
 if(t==NULL) return;    //If tree is NULL tree ,do nothing
 Node parent;
 Node temp;
 parent=temp=t;   //Still restore the root node of the tree
 bool flag=false;    //false is represent for left child,and true is represent for rihgt child
 while(temp)
 {
  if(key==temp->data)   //Find which one you want to del then do next
  {

/*

      three direction:

      I.If the node is the leaf node ,delete if straightly

      II.If the node have one child,then alter the parent node,let the child tree get temp->left or temp->right

      III.If the node have two child,this case have  a little complex,we need find the node temp's backward node,and move backward node to the node that will delete

*/
   if((temp->left==NULL)&&(temp->right==NULL))   
   {
    if(temp==t)   //If the node is the root head delete straightly
    {
     delete t;
    }
    else
    {
     if(! flag)
     {
      parent->left=NULL;
      delete temp;
     }
     else
     {
      parent->right=NULL;
      delete temp;
     }
    }
   }
   else
   if(temp->left==NULL)
   {
    if(! flag)
    {
     parent->left=temp->right;
     delete temp;
    }
    else
    {
     parent->right=temp->right;
     delete temp;
    }
    }
    else
     if(temp->right==NULL)
     {
      if(!flag)
      {
       parent->left=temp->left;
       delete temp;
      }
      else
      {
       parent->right=temp->left;
       delete temp;
      }
     }
     else
     {
      Node tt=temp->right;
      Node ttt=tt;
      while(tt)
      {
       ttt=tt;
       tt=tt->left;
      }
      parent=ttt;
      delete temp;

     }
     temp=NULL;
   
  }
  else
  if(key<temp->data)
  {
   parent=temp;
   flag=false;
   temp=temp->left;
  }
  else
  {
   parent=temp;
   flag=true;
   temp=temp->right;
  }

 }
}
void InOrder(Node t)
{
 if(t)
 {
  InOrder(t->left);
  cout<<t->data<<ends;
  InOrder(t->right);
 }
}
int _tmain(int argc, _TCHAR* argv[])
{
 int a[10];
 for(int i=0;i<10;i++)
 {
  a[i]=rand()%10;
  cout<<a[i]<<ends;
 }
 cout<<endl;
 Node t=NULL;
 CreateBST(t,a,10);
 DeleteBST(t,4);
 InOrder(t);
 
 system("pause");
 return 0;
}