Program to build a binary search tree from arrays.

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

struct node
{
struct node *left ;
char data ;
struct node *right ;
} ;

struct node * buildtree ( int ) ;
void inorder ( struct node * ) ;

char arr[ ] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', '\0', '\0', 'H' } ;
int lc[ ] = { 1, 3, 5, -1, 9, -1, -1, -1, -1, -1 } ;
int rc[ ] = { 2, 4, 6, -1, -1, -1, -1, -1, -1, -1 } ;

void main( )
{
struct node *root ;

clrscr( ) ;

root = buildtree ( 0 ) ;
printf ( “In-order Traversal:\n” ) ;
inorder ( root ) ;

getch( ) ;
}

struct node * buildtree ( int index )
{
struct node *temp = NULL ;
if ( index != -1 )
{
temp = ( struct node * ) malloc ( sizeof ( struct node ) ) ;
temp -> left = buildtree ( lc[index] ) ;
temp -> data = arr[index] ;
temp -> right = buildtree ( rc[index] ) ;
}
return temp ;
}

void inorder ( struct node *root )
{
if ( root != NULL )
{
inorder ( root -> left ) ;
printf ( "%c\t", root -> data ) ;
inorder ( root -> right ) ;
}
}