Binary search tree traversal using dynamic node representation

import java.io.*;
import java.util.*;


class Nodetype
{
int info;
Nodetype left;
Nodetype right;
Nodetype(int i)
{
info=i;
left=null;
right=null;
}
}


class Functions
{




Nodetype maketree(int x)
{
Nodetype node=new Nodetype(x);
return(node);
}/*end maketree*/


void setleft(Nodetype p,int x)
{
if(p==null)
System.out.println("\nInvalid insertion");
else
if(p.left!=null)
System.out.println("\nInvalid insertion");
else p.left=maketree(x);
}/*end setleft*/


void setright(Nodetype p,int x)
{
if(p==null)
System.out.println("\nInvalid insertion");
else
if(p.right!=null)
System.out.println("\nInvalid insertion");
else
p.right=maketree(x);
}/*end setright*/


void intrav(Nodetype ptree)
{
if(ptree!=null)
{
intrav(ptree.left);
System.out.print(ptree.info+" ");
intrav(ptree.right);
}
}/*end intrav*/


void pretrav(Nodetype ptree)
{
if(ptree!=null)
{
System.out.print(ptree.info+" ");
pretrav(ptree.left);
pretrav(ptree.right);
}
}/*end pretrav*/


void posttrav(Nodetype ptree)
{
if(ptree!=null)
{
posttrav(ptree.left);
posttrav(ptree.right);
System.out.print(ptree.info+" ");
}
}






void create()
{
Nodetype ptree,p,q;
int n,number=0,i;
System.out.print("\nEnter number of nodes : ");
n=getNumber();
System.out.println("\nEnter info "+n+" nodes :");
number=getNumber();
ptree=maketree(number);
for(i=1;i<n;i++)
{
number=getNumber();
p=q=ptree;
while(q!=null&&number!=p.info)
{
p=q;
if(number<p.info)
 q=p.left;
else
 q=p.right;
}
if(number==p.info)
System.out.println("Sorry !....."+number+"is a duplicate\n");
else
if(number<p.info)
setleft(p,number);
else
setright(p,number);
}
System.out.println("\nInorder   : ");
intrav(ptree);
System.out.println("\nPreorder  : ");
pretrav(ptree);
System.out.println("\nPostorder : ");
posttrav(ptree);
}


int getNumber()
{
String str;
int ne=0;
InputStreamReader input=new InputStreamReader(System.in);
BufferedReader in=new BufferedReader(input);
try
{
str=in.readLine();
ne=Integer.parseInt(str);
}
catch(Exception e)
{
System.out.println("I/O Error");
}
return ne;
}




}


class BSTTrav
{
public static void main(String arg[])
{
Functions f=new Functions();
f.create();


}/*end main*/
}




/*
Enter number of nodes : 4


Enter info 4 nodes :
1
2
3
4


Inorder   :
1 2 3 4
Preorder  :
1 2 3 4
Postorder :
4 3 2 1 Press any key to continue . . .
*/