源程序：
#include <stdio.h>
#include <stdlib.h>
//二叉排序树节点描述
typedef int DataType;
typedef struct Node
{
DataType key;
struct Node *lchild, *rchild;
struct Node *parent; //指向父节点指针
}Node, *pNode;
//采用插入法创建一棵二叉树
void insert(pNode *root, DataType key)
{
pNode p = (pNode)malloc(sizeof(Node));
p->key = key;
p->lchild = NULL;
p->rchild = NULL;
p->parent = NULL;
if ((*root) == NULL) //空树时，直接作为根节点
{
*root = p;
return;
}
if ((*root)->lchild == NULL && (*root)->key > key) //插入到当前节点(*root)的左孩子
{
p->parent = (*root);
(*root)->lchild = p;
return;
}
if ((*root)->rchild == NULL && (*root)->key < key) //插入到当前节点(*root)的右孩子
{
p->parent = (*root);
(*root)->rchild = p;
return;
}
if ((*root)->key > key)
insert(&(*root)->lchild, key);
else if ((*root)->key < key)
insert(&(*root)->rchild, key);
else
return;
}
void create(pNode *root, DataType *keyArray, int length)
{
int i;
for (i = 0; i<length; i++)
insert(root, keyArray[i]); //逐个节点插入二叉树
}
//查找元素
pNode search(pNode root, DataType key)
{
if (root == NULL)
return NULL;
else if (key > root->key)
return search(root->rchild, key);
else if (key < root->key)
return search(root->lchild, key);
else
return root;
}
void inordertraverse(pNode root)
{
if (root)
{
inordertraverse(root->lchild);
printf("%4d", root->key);
inordertraverse(root->rchild);
}
}
/////////////////////////////////////////////////////////////
//链队列的定义
typedef struct LinkQueueNode
{
int data;
struct LinkQueueNode *next;
}LkQueNode;
typedef struct LkQueue
{
LkQueNode *front, *rear;
}LkQue;
//LkQue LQ;
//初始化链队列
void InitQueue(LkQue *LQ)
{
LkQueNode *temp;
temp = (LkQueNode *)malloc(sizeof(LkQueNode));
LQ->front = temp;
LQ->rear = temp;
(LQ->front)->next = NULL;
}
//判断链队列空
int EmptyQueue(LkQue *LQ)
{
return LQ->front == LQ->rear;
}
//入链队列
void EnQueue(LkQue *LQ, int x)
{
LkQueNode *temp;
temp = (LkQueNode *)malloc(sizeof(LkQueNode));
temp->data = x;
temp->next = NULL;
(LQ->rear)->next = temp;
LQ->rear = temp;
}
//出链队列
int outQueue(LkQue *LQ)
{
LkQueNode *temp;
if (EmptyQueue(LQ))
{
printf("空队列！");
return 0;
}
else
{
temp = (LQ->front)->next;
(LQ->front)->next = temp->next;
if (temp->next == NULL)
LQ->rear = LQ->front;
free(temp);
return 1;
}
}
//取队列首元素
int Gethead(LkQue *LQ)
{
LkQueNode *temp;
if (EmptyQueue(LQ))
return 0;
else
{
temp = (LQ->front)->next;
return temp->data;
}
}
//按层次遍历二叉排序树，借助数组实现
void levelorder(pNode bt)
{
pNode q[100];
int front = 0, rear = 0;
pNode p;
if (bt == NULL)
return;
q[rear] = bt;
rear = (rear + 1) % 100;
while (front != rear)
{
p = q[front];
front = (front + 1) % 100;
printf("%4d", p->key);
if (p->lchild)
{
q[rear] = p->lchild;
rear = (rear + 1) % 100;
}
if (p->rchild)
{
q[rear] = p->rchild;
rear = (rear + 1) % 100;
}
}
}
/////////////////////////////////////////////////////////////
void main()
{
pNode root = NULL;
DataType nodeArray[11] = { 15,6,18,3,7,17,20,2,4,13,9 };
int i;
printf("待查找数据为：\n");
for (i = 0; i<11; i++)
printf("%4d", nodeArray[i]);
create(&root, nodeArray, 11);
printf("\n\n");
printf("中序遍历输出二叉树结点的值\n");
inordertraverse(root);
printf("\n\n");
//按层次遍历二叉排序树，需借助队列实现
printf("按层次遍历二叉排序树\n");
levelorder(root);
printf("\n请输入要查找的元素的值:");
DataType locate;
scanf("%d", &locate);
if (search(root, locate) != NULL)
printf("这些数中有你要查找的数%d\n", search(root, locate)->key);
else
printf("这些数据中没有你要查找的数。\n");
system("pause");
}
运行结果：
