binary tree operations from http://zhedahht.blog.163.com/blog/static/25411174200732975328975/ and more.

algos_binary_tree_ops.c

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

struct SBinaryTreeNode // a node of the binary tree
{
	int               m_nValue; // value of node
	struct SBinaryTreeNode  *m_pLeft;  // left child of node
	struct SBinaryTreeNode  *m_pRight; // right child of node
};

///////////////////////////////////////////////////////////////////////
// Get depth of a binary tree
// Input: pTreeNode - the head of a binary tree
// Output: the depth of a binary tree
///////////////////////////////////////////////////////////////////////
int TreeDepth(struct SBinaryTreeNode *pTreeNode)
{
	// the depth of a empty tree is 0
	if (!pTreeNode)
		return 0;

	// the depth of left sub-tree
	int nLeft = TreeDepth(pTreeNode->m_pLeft);
	// the depth of right sub-tree
	int nRight = TreeDepth(pTreeNode->m_pRight);

	// depth is the binary tree
	return (nLeft > nRight) ? (nLeft + 1) : (nRight + 1);
}

///////////////////////////////////////////////////////////////////////
// Get number of the nodes
// Input: pTreeNode - the head of a binary tree
// Output: the number of the nodes
///////////////////////////////////////////////////////////////////////
int NodesNumber(struct SBinaryTreeNode *pTreeNode)
{
	// the number of the nodes is 0
	if (!pTreeNode)
		return 0;

	return NodesNumber(pTreeNode->m_pLeft) + \
				NodesNumber(pTreeNode->m_pRight) + 1;
}

void Visit(struct SBinaryTreeNode *pTreeNode)
{
	if (!pTreeNode)
	return;
	printf(" %d", pTreeNode->m_nValue);
}

void PreOrderTraverse(struct SBinaryTreeNode *pTreeNode)
{
	if (pTreeNode == NULL)
		return;

	Visit(pTreeNode); // root
	PreOrderTraverse(pTreeNode->m_pLeft); // left sub-tree
	PreOrderTraverse(pTreeNode->m_pRight); // right sub-tree
}

void InOrderTraverse(struct SBinaryTreeNode *pTreeNode)
{
	if (pTreeNode == NULL)
		return;
	InOrderTraverse(pTreeNode->m_pLeft); // left sub-tree
	Visit(pTreeNode); // root
	InOrderTraverse(pTreeNode->m_pRight); // right sub-tree
}

void PostOrderTraverse(struct SBinaryTreeNode *pTreeNode)
{
	if (pTreeNode == NULL)
		return;
	PostOrderTraverse(pTreeNode->m_pLeft); // left sub-tree
	PostOrderTraverse(pTreeNode->m_pRight); // right sub-tree
	Visit(pTreeNode); // root
}

int main()
{
	struct SBinaryTreeNode *ROOT = malloc(sizeof(struct SBinaryTreeNode));
	struct SBinaryTreeNode *N1 = malloc(sizeof(struct SBinaryTreeNode));
	struct SBinaryTreeNode *N2 = malloc(sizeof(struct SBinaryTreeNode));
	struct SBinaryTreeNode *N3 = malloc(sizeof(struct SBinaryTreeNode));
	struct SBinaryTreeNode *N4 = malloc(sizeof(struct SBinaryTreeNode));
	struct SBinaryTreeNode *N5 = malloc(sizeof(struct SBinaryTreeNode));

	ROOT->m_pLeft = N1;
	ROOT->m_pRight = N2;
	ROOT->m_nValue = 10;

	N1->m_pLeft = N3;
	N1->m_pRight = NULL;
	N1->m_nValue = 6;

	N2->m_pLeft = N4;
	N2->m_pRight = N5;
	N2->m_nValue = 14;

	N3->m_pLeft = NULL;
	N3->m_pRight = NULL;
	N3->m_nValue = 4;

	N4->m_pLeft = NULL;
	N4->m_pRight = NULL;
	N4->m_nValue = 12;

	N5->m_pLeft = NULL;
	N5->m_pRight = NULL;
	N5->m_nValue = 16;

/*
*      10
*     /  \
*    6   14
*   /   / \
*  4   12 16
*
*/


	printf("binary tree depth: %d\n", TreeDepth(ROOT));
	printf("number of nodes: %d\n", NodesNumber(ROOT));

	PreOrderTraverse(ROOT);

	printf("\n");

	InOrderTraverse(ROOT);

	printf("\n");

	PostOrderTraverse(ROOT);

	printf("\n");

	free(ROOT);
	free(N1);
	free(N2);
	free(N3);
	free(N4);
	free(N5);

    return 0;
}