C Program to Implement Binary Tree using Linked List

C Program to Implement Binary Tree using Linked List - Source code

struct node {
    struct node * left;
    char data;
    struct node * right;
};
 
struct node *constructTree( int );
void inorder(struct node *);
 
char array[ ] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', '\0', '\0', 'H' };
int leftcount[ ] = {  1,   3,   5,   -1,   9,  -1,  -1,   -1,   -1,  -1 };
int rightcount[ ] = {  2,   4,   6,   -1,  -1,  -1,  -1,   -1,   -1,  -1 };
 
void main() {
    struct node *root;
    root = constructTree( 0 );
    printf("In-order Traversal: \n");
    inorder(root);
}
 
struct node * constructTree( int index ) {
    struct node *temp = NULL;
    if (index != -1) {
        temp = (struct node *)malloc( sizeof ( struct node ) );
        temp->left = constructTree( leftcount[index] );
        temp->data = array[index];
        temp->right = constructTree( rightcount[index] );
    }
    return temp;
}
 
void inorder( struct node *root ) {
    if (root != NULL) {
        inorder(root->left);
        printf("%c\t", root->data);
        inorder(root->right);
    }
}

Program Output

In-order Traversal:
D       B       H       E       A       F       C       G