Write C code to implement the preorder(), inorder() and postorder() traversals. Whats their time complexities?

Here are the C program snippets to implement these traversals...
Preorder

preorder(mynode *root)

{

  if(root)

  {

    printf("Value : [%d]", root->value);

    preorder(root->left);

    preorder(root->right);

  }

}

postorder(mynode *root)

{

  if(root)

  {

    postorder(root->left);

    postorder(root->right);

    printf("Value : [%d]", root->value);

  }

}

inorder(mynode *root)

{

  if(root)

  {

    inorder(root->left);

    printf("Value : [%d]", root->value);

    inorder(root->right);

  }

}