i tried to make a binary tree, but when i print it, it shows nothing.

can someone help me? here's the code:

Code:#include<iostream> #include<Windows.h> #include<string> #include<fstream> #include<cstdarg> using namespace std; struct data { int num; struct data *left, *right; }*root = NULL; void insert(int num, struct data *node) { if(node == NULL) { node = new data; node->num = num; node->left = node->right = NULL; } else { if(num < node->num) { insert(num, node->left); } else if(num > node->num) { insert(num, node->right); } } } void print(struct data *node) { if(node!=NULL) { print(node->left); cout << node->num << " "; print(node->right); } } int main() { insert(6, root); insert(4, root); insert(7, root); insert(3, root); insert(8, root); print(root); cin.get(); return 0; }