Most simple binary tree implementation in C

bin_tree.c

#include <stdio.h>
#include <stdlib.h>

// node structure
typedef struct node_s
{
    int value;
    struct node_s *lnode;
    struct node_s *rnode;
} node_t;

// compare nodes values
int tree_compare_nodes(node_t *lnode, node_t *rnode)
{
    if ( lnode->value < rnode->value )
    {
        return -1;
    }
    else if ( lnode->value > rnode->value )
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

// insert node into the tree
void tree_insert_node (int val, node_t **tree)
{
    // create new node if doesn't exist
    if ( *tree == NULL )
    {
        *tree = malloc( sizeof(node_t) );
        (*tree)->value = val;
        (*tree)->lnode = NULL;
        (*tree)->rnode = NULL;
        return;
    }

    // insert on the left if smaller
    if ( (*tree)->value < (*tree)->value )
    {
        tree_insert_node(val, &(*tree)->lnode);
    }
    // insert on the right if bigger
    else if ( (*tree)->value > (*tree)->value )
    {
        tree_insert_node( val, &(*tree)->rnode);
    }
}

// locate a node in the tree
node_t *tree_search_node (int val, node_t *tree)
{
    if (tree != NULL)
    {
        if (val == tree->value)
        {
            return tree;
        }
        else if (val < tree->value)
        {
            return tree_search_node(val, tree->lnode);
        }
        else
        {
            return tree_search_node(val, tree->rnode);
        }
    }
    else
    {
        return NULL;
    }
}

void tree_traverse(node_t *tree)
{
    if ( tree->lnode )
    {
        tree_traverse(tree->lnode);
    }
    printf("%d\n", tree->value);
    if ( tree->rnode )
    {
        tree_traverse(tree->rnode);
    }
}

// deconstruct the tree
void tree_destruct (node_t *tree)
{
    if (tree != NULL)
    {
        tree_destruct(tree->lnode);
        tree_destruct(tree->rnode);
        free(tree);
    }
}

int main (int argc, char *argv)
{
    node_t *tree = NULL;

    tree_insert_node(50,  &tree);
    tree_insert_node(25,  &tree);
    tree_insert_node(100, &tree);
    tree_insert_node(20,  &tree);

    tree_traverse(tree);

    tree_destruct(tree);
    return EXIT_SUCCESS;
}