Write me a binary tree traversal in C language

I can give you an example: #include <stdio.h> struct node { int data; struct node left, right; }; / function to print leaf nodes of a binary tree / void printLeaves(struct node* root) { if ( root != NULL ) { printLeaves(root->left);

// 如果节点为叶子节点，则打印
    if ( root-