binary search tree

bst.c

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

typedef struct bstNode {
    int data;
    struct bstNode* left;
    struct bstNode* right;
}bstNode;

bstNode* GetNewNode (int data);
bstNode* insertNode(bstNode* root, int data);
bool search_bst (bstNode* root, int data);

bstNode* GetNewNode (int data){
    bstNode* newNode = NULL;
    if ((newNode = malloc (sizeof (bstNode))) == NULL){
        printf ("Node create error!\n");
        exit (-1);
    }
    newNode->data = data;
    newNode->left = NULL, newNode->right = NULL;
    return newNode;
}

bstNode* insertNode(bstNode* root, int data){
    if (root == NULL)
        root = GetNewNode (data);
    else if (data <= root->data)
        root->left = insertNode (root->left, data);
    else
        root->right = insertNode (root->right, data);

    return root;
}

bool search_bst (bstNode* root, int data){
    if (root == NULL)
        return false;
    else if (root->data == data)
        return true;
    else if (data <= root->data)
        return search_bst (root->right, data);
    else
        return search_bst (root->left, data);
}

int main (void){
    int value;

    bstNode* root = NULL;
    root = insertNode (root, 15);
    root = insertNode (root, 10);
    root = insertNode (root, 20);
    root = insertNode (root, 25);
    root = insertNode (root, 8);
    root = insertNode (root, 12);
    printf ("root: %p\n", (void*) root);

    printf ("Insert a number to search:\n");
    scanf ("%d", &value);

    if (search_bst (root, value))
        printf ("Found!\n");
    else
        printf ("Not found!\n");

    return 0;
}