Notes

#include<stdio.h>
#include<stdlib.h>

struct node
{
int info;
struct node *llink;
struct node *rlink;
};
typedef struct node* NODE;



NODE getnode()
{
NODE x;
x=(NODE)malloc(sizeof(struct node));
if (x==NULL)
{
printf ("out of memoryn");
exit(0);
}
return x;

}

NODE insert(int item,NODE root)
{
NODE temp,cur,prev;
temp=getnode();
temp->info=item;
temp->rlink=temp->llink=NULL;
if (root==NULL)
{
root=temp;
return root;
}
else
{
prev=NULL;
cur=root;
while(cur!=NULL)
{
prev=cur;
if (temp->info<cur->info)
cur=cur->llink;
else
cur=cur->rlink;
}
if(temp->info<prev->info)
prev->llink=temp;
else
prev->rlink=temp;
return root;
}
}

void pre(NODE PRE)
{

{
printf ("%dt",PRE->info);
pre(PRE->llink);
pre(PRE->rlink);
}
}

void in(NODE IN)
{
if(IN!=NULL)
{
pre(IN->llink);
printf ("%dt",IN->info);
pre(IN->rlink);
}
}

void post(NODE POST)
{
if(POST!=NULL)
{
post(POST->llink);
post(POST->rlink);
printf ("%dt",POST->info);
}
}

void traversal(NODE root)
{
NODE IN,POST,PRE;
IN=root;
PRE=root;
POST=root;
if(root==NULL)
printf ("Emptyn");
else
{
printf ("preorder:n");
pre(PRE);
printf ("inorder:n");
in(IN);
printf ("postorder:n");
post(POST);
}
}
void search(NODE root)
{
int item,i=0;
NODE cur;
printf ("Enter element to be searched:");
scanf ("%d",&item);
if (root==NULL)
{
printf ("Emptyn");
return;
}
cur=root;
while(cur!=NULL)
{
if(item==cur->info)
{
i++;
printf ("found at %dn",cur->info);

}
if (item<cur->info)
cur=cur->llink;
else
cur=cur->rlink;
}
if (i==0)
printf ("key not foundn");
return;
}

void main()
{
int choice,item;
NODE root=NULL;
while (1)
{
printf ("1.Create BST 2.Traversal 3.Searchn");
scanf("%d",&choice);
switch(choice)
{
case 1:printf ("Enter item to be inserted:");
scanf ("%d",&item);
insert(item,root);break;
case 2:traversal(root);break;
case 3:search(root);break;
default:printf ("invalid choicen");
}
}
}