Notes

Binary Search Tree
#include<iostream>
#include<conio.h>
using namespace std;
typedef struct node
{
int info;
struct node *left,*right;
}node;

node *root=NULL,*paptr=NULL,*chptr=root,*ptr,*temp;
void insertion(int item);
void preorder(node *ptr);
void postorder(node *ptr);
void inorder(node *ptr);
node *searchh(int item);
int choice,val;
char ch;
int main()
{
do{
cout<<"1. To insert n2. To traverse in preorder n3. To traverse in postordern4. To traverse in inordern5.Searching"<<endl;
cin>>choice;
switch(choice)
{
case 1:{
cout<<"Enter value to insert"<<endl;
cin>>val;
insertion(val);}
break;
case 2 : { preorder(root);}
break;
case 3 : { postorder(root);}
break;
case 4 : { inorder(root);}
break;
case 5 : {
cout<<"enter item to search"<<endl;
cin>>val;
temp=searchh(val);
if(temp==NULL)
cout<<"element not present"<<endl;
else
cout<<"element present at :"<<&temp<<endl;
break;
}
}
cout<<"Press Y to enter again" <<endl;
cin>>ch;
}while(ch=='y');
}

void insertion(int item)
{
ptr = new node;
ptr->left=NULL;
ptr->right=NULL;
ptr->info=item;
if(root==NULL)
{
root=ptr;
return ;
}
paptr=NULL;
chptr=root;
while(chptr!=NULL)
{
paptr=chptr;
if(item<chptr->info)
{
chptr=chptr->left;
}
else{
chptr=chptr->right;
}
}
if(item<paptr->info)
{
paptr->left=ptr;
}
else
{
paptr->right=ptr;
}
}



void preorder(node *ptr)
{
if(ptr!=NULL)
{
cout<<ptr->info<<endl;
preorder(ptr->left);
preorder(ptr->right);
}
}




void postorder(node *ptr)
{
if(ptr!=NULL)
{
postorder(ptr->left);
postorder(ptr->right);
cout<<ptr->info<<endl;
}
}




void inorder(node *ptr)
{
if(ptr!=NULL)
{
inorder(ptr->left);
cout<<ptr->info<<endl;
inorder(ptr->right);
}
}


node *searchh(int item)
{
paptr=NULL;
chptr=root;
while(chptr!=NULL)
{
if(chptr->info==item)
return chptr;
paptr=chptr;
if(item<chptr->info)
chptr=chptr->left;
else
chptr=chptr->right;
}
return NULL;
}