A Simple C Code for Binary Tree Traversal

Three traversal methods
     i)   preorder traversal
     ii)  inorder traversal
     iii) postorder traversal

This post may seem very simple . But to solve the problems related to binary trees you should have clear understanding of these traversals . For an example ,creating mirror image of the tree depends on postorder traversal .
Consider the following tree

 Preorder  :  A B C D E F G
 Inorder   :   C B D A F E G
 Postorder : C D B F G E A

 Code :(in C)

 Preorder Traversal :

 void preorder_traversal(struct node * node)
 {
if(node!=null)
{
printf("%d ",node->data);
preorder_traversal(node->left);
preorder_traversal(node->right);
}
 }

 Inorder Traversal :

 void inorder_traversal(struct node * node)
 {
if(node!=null)
{
inorder_traversal(node->left);
printf("%d ",node->data);
inorder_traversal(node->right);
}
 }

 Postorder Traversal :

 void postorder_traversal(struct node * node)
 {
if(node!=null)
{
postorder_traversal(node->left);
postorder_traversal(node->right);
printf("%d ",node->data);
}
 }

Please let me know if there is any bug in the above code and your suggestions are always welcome .