Binary search tree implementation in C

bst.c

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

typedef struct node Node;

struct node {
    int value;
    Node *left;
    Node *right;
};

Node* insert(Node *root, int v) {
    if (root == NULL) {
        root = malloc(sizeof (Node));
        root->value = v;
        root->left = NULL;
        root->right = NULL;
    } else if (v < root->value) {
        root->left = insert(root->left, v);
    } else {
        root->right = insert(root->right, v);
    }

    return root;
}

void traverse(Node *root) {
    if (root == NULL) {
        return;
    }

    traverse(root->left);
    traverse(root->right);
}

int main(int argc, char** argv) {
    Node *root = NULL;
    const int SIZE = 2000000;
    int *a = malloc(sizeof (int)*SIZE);
    clock_t start, end;

    printf("Generating random array with %d values...\n", SIZE);

    start = clock();

    for (int i = 0; i < SIZE; i++) {
        a[i] = rand() % 10000;
    }

    end = clock();

    printf("Done. Took %f seconds\n\n", (double) (end - start) / CLOCKS_PER_SEC);
    printf("Filling the tree with %d nodes...\n", SIZE);

    start = clock();

    for (int i = 0; i < SIZE; i++) {
        root = insert(root, a[i]);
    }

    end = clock();
    free(a);

    printf("Done. Took %f seconds\n\n", (double) (end - start) / CLOCKS_PER_SEC);
    printf("Traversing all %d nodes in tree...\n", SIZE);

    start = clock();

    traverse(root);

    end = clock();
    free(root);

    printf("Done. Took %f seconds\n\n", (double) (end - start) / CLOCKS_PER_SEC);

    return (EXIT_SUCCESS);
}

`void freeForBtree(Node * root){
if(root==NULL)
{
return;
}
free(root);
else{
freeForBtree(root->left);
freeForBtree(root->right);
}
}'
this is the free routine I have write for your program, I hope it's not wrong,hhh