Binary Tree Sorting

/* Binary Tree Sorting. */

#include <stdio.h>
#include <conio.h>
#include <alloc.h>

struct btreenode
{
struct btreenode *leftchild ;
int data ;
struct btreenode *rightchild ;
} ;

void insert ( struct btreenode **, int ) ;
void inorder ( struct btreenode * ) ;

void main( )
{
struct btreenode *bt ;
int arr[10] = { 11, 2, 9, 13, 57, 25, 17, 1, 90, 3 } ;
int i ;

bt = NULL ;

clrscr( ) ;

printf ( "Binary tree sort.\n" ) ;

printf ( "\nArray:\n" ) ;
for ( i = 0 ; i <= 9 ; i++ )
printf ( "%d\t", arr[i] ) ;

for ( i = 0 ; i <= 9 ; i++ )
insert ( &bt, arr[i] ) ;

printf ( "\nIn-order traversal of binary tree:\n" ) ;
inorder ( bt ) ;

getch( ) ;
}

void insert ( struct btreenode **sr, int num )
{
if ( *sr == NULL )
{
*sr = malloc ( sizeof ( struct btreenode ) ) ;

( *sr ) -> leftchild = NULL ;
( *sr ) -> data = num ;
( *sr ) -> rightchild = NULL ;
}
else
{
if ( num < ( *sr ) -> data )
insert ( &( ( *sr ) -> leftchild ), num ) ;
else
insert ( &( ( *sr ) -> rightchild ), num ) ;
}
}

void inorder ( struct btreenode *sr )
{
if ( sr != NULL )
{
inorder ( sr -> leftchild ) ;
printf ( "%d\t", sr -> data ) ;
inorder ( sr -> rightchild ) ;
}
}