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 ) ;
    }
}