ツリーでxの値を持つノードを探します(すべてのノードの値が異なると仮定します)

#include
#include
#define N 7
using namespace std;

typedef struct node
{
	struct node *leftChild;
	struct node *rightChild;
	int data;
}BiTreeNode, *BiTree;

//       
BiTreeNode *createNode(int i)
{
	BiTreeNode * q = new BiTreeNode;
	q->leftChild = NULL;
	q->rightChild = NULL;
	q->data = i;

	return q;
}

BiTree createBiTree()
{
	BiTreeNode *p[N];
	int i;
	for(i = 0; i < N; i++)
		p[i] = createNode(i + 1);

	//        
	for(i = 0; i < N/2; i++)
	{
		p[i]->leftChild = p[i * 2 + 1];
		p[i]->rightChild = p[i * 2 + 2];
	}

	return p[0];
}

BiTreeNode *findElement(BiTree T, int element)
{
	if(NULL == T)
		return NULL;

	if(element == T->data)
		return T;

	BiTreeNode *p = findElement(T->leftChild, element);
	if(NULL != p)
		return p;

	return  findElement(T->rightChild, element);
}

int main()
{
	BiTree T = createBiTree();
	BiTreeNode *p; 

	p = findElement(T, 0);
	cout << p << endl;       
	cout << "************" << endl; 

	p = findElement(T, 8);
	cout << p << endl;       
	cout << "************" << endl; 

	p = findElement(T, 1);
	cout << p->data << endl;
	cout << p->leftChild->data << endl;
	cout << p->rightChild->data << endl;
	cout << "************" << endl; 

	p = findElement(T, 2);
	cout << p->data << endl;
	cout << p->leftChild->data << endl;
	cout << p->rightChild->data << endl;
	cout << "************" << endl; 

	p = findElement(T, 3);
	cout << p->data << endl;
	cout << p->leftChild->data << endl;
	cout << p->rightChild->data << endl;
	cout << "************" << endl; 

	p = findElement(T, 4);
	cout << p->data << endl;
	cout << p->leftChild << endl;
	cout << p->rightChild << endl;
	cout << "************" << endl; 

	p = findElement(T, 5);
	cout << p->data << endl;
	cout << p->leftChild << endl;
	cout << p->rightChild << endl;
	cout << "************" << endl; 

	p = findElement(T, 6);
	cout << p->data << endl;
	cout << p->leftChild << endl;
	cout << p->rightChild << endl;
	cout << "************" << endl; 

	p = findElement(T, 7);
	cout << p->data << endl;
	cout << p->leftChild << endl;
	cout << p->rightChild << endl;
	cout << "************" << endl; 

	return 0;
}

結果は次のとおりです.
00000000 ************ 1 2 3 ************ 2 4 5 ************ 3 6 7 ************ 4 00000000 00000000 ************ 5 00000000 00000000 ************ 6 00000000 00000000 ************ 7 00000000 00000000 ************