/************************************************************************/二叉树在C语言中的实现与应用/************************************************************************/#include <stdio.h>#include <stdlib.h>#define STACK_MAX_SIZE 30#define QUEUE_MAX_SIZE 30#ifndef elemTypetypedef char elemType;#endif/************************************************************************//* 以下是关于二叉树操作的11个简单算法 *//************************************************************************/ struct BTreeNode{elemType data;struct BTreeNode *left;struct BTreeNode *right;};/* 1.初始化二叉树 */void initBTree(struct BTreeNode* *bt){*bt = NULL;return;}/* 2.建立二叉树(根据a所指向的二叉树广义表字符串建立) */void createBTree(struct BTreeNode* *bt, char *a){struct BTreeNode *p;struct BTreeNode *s[STACK_MAX_SIZE];/* 定义s数组为存储根结点指针的栈使用 */int top = -1; /* 定义top作为s栈的栈顶指针，初值为-1,表示空栈 */int k; /* 用k作为处理结点的左子树和右子树，k = 1处理左子树，k = 2处理右子树 */ int i = 0; /* 用i扫描数组a中存储的二叉树广义表字符串，初值为0 */*bt = NULL; /* 把树根指针置为空，即从空树开始建立二叉树 *//* 每循环一次处理一个字符，直到扫描到字符串结束符\0为止 */while(a[i] != '\0'){switch(a[i]){case ' ':break; /* 对空格不作任何处理 */case '(':if(top == STACK_MAX_SIZE - 1){printf("栈空间太小！\n");exit(1);}top++;s[top] = p;k = 1;break;case ')':if(top == -1){printf("二叉树广义表字符串错误!\n");exit(1);}top--;break;case ',':k = 2;break;default:p = new BTreeNode ;p->data = a[i];p->left = p->right = NULL;if(*bt == NULL){*bt = p;}else{if( k == 1){s[top]->left = p;}else{s[top]->right = p;}}}i++; /* 为扫描下一个字符修改i值 */}return;}/* 3.检查二叉树是否为空，为空则返回1,否则返回0 */ int emptyBTree(struct BTreeNode *bt){if(bt == NULL){return 1;}else{return 0;}}/* 4.求二叉树深度 */int BTreeDepth(struct BTreeNode *bt){if(bt == NULL){return 0; /* 对于空树，返回0结束递归 */}else{int dep1 = BTreeDepth(bt->left); /* 计算左子树的深度 */int dep2 = BTreeDepth(bt->right); /* 计算右子树的深度 */if(dep1 > dep2){return dep1 + 1;}else{return dep2 + 1;}}}/* 5.从二叉树中查找值为x的结点，若存在则返回元素存储位置，否则返回空值 */ elemType *findBTree(struct BTreeNode *bt, elemType x){if(bt == NULL){return NULL;}else{if(bt->data == x){return &(bt->data);}else{ /* 分别向左右子树递归查找 */elemType *p;if(p = findBTree(bt->left, x)){return p;}if(p = findBTree(bt->right, x)){return p;}return NULL;}}}/* 6.输出二叉树(前序遍历) */void printBTree(struct BTreeNode *bt){/* 树为空时结束递归，否则执行如下操作 */if(bt != NULL){printf("%c", bt->data); /* 输出根结点的值 */if(bt->left != NULL || bt->right != NULL){printf("(");printBTree(bt->left);if(bt->right != NULL){printf(",");}printBTree(bt->right);printf(")");}}return;}/* 7.清除二叉树，使之变为一棵空树 */void clearBTree(struct BTreeNode* *bt) {if(*bt != NULL){clearBTree(&((*bt)->left));clearBTree(&((*bt)->right));free(*bt);*bt = NULL;}return;}/* 8.前序遍历 */void preOrder(struct BTreeNode *bt){if(bt != NULL){printf("%c ", bt->data); /* 访问根结点 */ preOrder(bt->left); /* 前序遍历左子树 */ preOrder(bt->right); /* 前序遍历右子树 */ }return;}/* 9.前序遍历 */void inOrder(struct BTreeNode *bt){if(bt != NULL){inOrder(bt->left); /* 中序遍历左子树 */ printf("%c ", bt->data); /* 访问根结点 */ inOrder(bt->right); /* 中序遍历右子树 */ }return;}/* 10.后序遍历 */void postOrder(struct BTreeNode *bt){if(bt != NULL){postOrder(bt->left); /* 后序遍历左子树 */ postOrder(bt->right); /* 后序遍历右子树 */ printf("%c ", bt->data); /* 访问根结点 */ }return;}/* 11.按层遍历 */void levelOrder(struct BTreeNode *bt){struct BTreeNode *p;struct BTreeNode *q[QUEUE_MAX_SIZE];int front = 0, rear = 0;/* 将树根指针进队 */if(bt != NULL){rear = (rear + 1) % QUEUE_MAX_SIZE;q[rear] = bt;}while(front != rear){ /* 队列非空 */front = (front + 1) % QUEUE_MAX_SIZE; /* 使队首指针指向队首元素 */p = q[front];printf("%c ", p->data);/* 若结点存在左孩子，则左孩子结点指针进队 */if(p->left != NULL){rear = (rear + 1) % QUEUE_MAX_SIZE;#include <stdio.h>#include <stdlib.h>#define STACK_MAX_SIZE 30#define QUEUE_MAX_SIZE 30#ifndef elemTypetypedef char elemType ;#endif/************************************************************************//* 以下是关于二叉树操作的11个简单算法 *//************************************************************************/struct BTreeNode{elemType data ;struct BTreeNode *left ;struct BTreeNode *right ;};/* 1.初始化二叉树 */void initBTree(struct BTreeNode* *bt){*bt = NULL ;return ;}/* 2.建立二叉树(根据a所指向的二叉树广义表字符串建立) */void createBTree(struct BTreeNode* *bt, char *a){struct BTreeNode *p;struct BTreeNode *s[STACK_MAX_SIZE];/* 定义s数组为存储根结点指针的栈使用 */int top = -1; /* 定义top作为s栈的栈顶指针，初值为-1,表示空栈 */int k ; /* 用k作为处理结点的左子树和右子树，k = 1处理左子树，k = 2处理右子树 */ int i = 0 ; /* 用i扫描数组a中存储的二叉树广义表字符串，初值为0 */*bt = NULL ; /* 把树根指针置为空，即从空树开始建立二叉树 *//* 每循环一次处理一个字符，直到扫描到字符串结束符\0为止 */ while(a[i] != '\0'){switch(a[i]){case ' ':break; /* 对空格不作任何处理 */case '(':if( top == STACK_MAX_SIZE - 1 ){printf("栈空间太小！\n") ;exit(1) ;}top++ ;s[top] = p ;k = 1 ;break;case ')':if(top == -1){printf("二叉树广义表字符串错误!\n");exit(1);}top-- ;break ;case ',':k = 2;break;default:p = new BTreeNode ;p->data = a[i] ;p->left = p->right = NULL ;if( *bt == NULL){*bt = p ;}else{if( k == 1){s[top]->left = p ;}else{s[top]->right = p ;}}}i++ ; /* 为扫描下一个字符修改i值 */}return;}/* 3.检查二叉树是否为空，为空则返回1,否则返回0 */int emptyBTree(struct BTreeNode *bt){if(bt == NULL){return 1;}else{return 0;}}/* 4.求二叉树深度 */int BTreeDepth(struct BTreeNode *bt){if(bt == NULL){return 0; /* 对于空树，返回0结束递归 */}else{int dep1 = BTreeDepth(bt->left); /* 计算左子树的深度 */int dep2 = BTreeDepth(bt->right); /* 计算右子树的深度 */if(dep1 > dep2){return dep1 + 1;}else{return dep2 + 1;}}}/* 5.从二叉树中查找值为x的结点，若存在则返回元素存储位置，否则返回空值 */ elemType *findBTree(struct BTreeNode *bt, elemType x){if(bt == NULL){return NULL;}else{if(bt->data == x){return &(bt->data);}else{ /* 分别向左右子树递归查找 */elemType *p ;if(p = findBTree(bt->left, x)){return p ;}if(p = findBTree(bt->right, x)){return p ;}return NULL ;}}}/* 6.输出二叉树(前序遍历) */void printBTree(struct BTreeNode *bt){/* 树为空时结束递归，否则执行如下操作 */if(bt != NULL){printf("%c ", bt->data); /* 输出根结点的值 */ if(bt->left != NULL || bt->right != NULL){printf("(") ;printBTree(bt->left) ;if(bt->right != NULL){printf(",") ;}printBTree(bt->right) ;printf(")");}}return;}/* 7.清除二叉树，使之变为一棵空树 */void clearBTree(struct BTreeNode* *bt){if(*bt != NULL){clearBTree(&((*bt)->left)) ;clearBTree(&((*bt)->right)) ;free(*bt) ;*bt = NULL ;}return ;}/* 8.前序遍历 */void preOrder(struct BTreeNode *bt){if(bt != NULL){printf("%c ", bt->data) ; /* 访问根结点 */ preOrder(bt->left) ; /* 前序遍历左子树 */ preOrder(bt->right) ; /* 前序遍历右子树 */}return ;}/* 9.中序遍历 */void inOrder(struct BTreeNode *bt){if(bt != NULL){inOrder(bt->left); /* 中序遍历左子树 */printf("%c ", bt->data); /* 访问根结点 */inOrder(bt->right); /* 中序遍历右子树 */}return;}/* 10.后序遍历 */void postOrder(struct BTreeNode *bt){if(bt != NULL){postOrder(bt->left); /* 后序遍历左子树 */postOrder(bt->right); /* 后序遍历右子树 */printf("%c ", bt->data); /* 访问根结点 */}return;}/* 11.按层遍历 */void levelOrder(struct BTreeNode *bt){struct BTreeNode *p;struct BTreeNode *q[QUEUE_MAX_SIZE];int front = 0, rear = 0;/* 将树根指针进队 */if(bt != NULL){rear = (rear + 1) % QUEUE_MAX_SIZE;q[rear] = bt;}while(front != rear){ /* 队列非空 */front = (front + 1) % QUEUE_MAX_SIZE; /* 使队首指针指向队首元素 */ p = q[front];printf("%c ", p->data);/* 若结点存在左孩子，则左孩子结点指针进队 */if(p->left != NULL){rear = (rear + 1) % QUEUE_MAX_SIZE;q[rear] = p->left;}/* 若结点存在右孩子，则右孩子结点指针进队 */if(p->right != NULL){rear = (rear + 1) % QUEUE_MAX_SIZE;q[rear] = p->right;}}return;}/************************************************************************/int main(int argc, char *argv[]){struct BTreeNode *bt ; /* 指向二叉树根结点的指针 */char *b ; /* 用于存入二叉树广义表的字符串 */elemType x, *px ;initBTree(&bt) ;printf("输入二叉树广义表的字符串：\n") ;/* scanf("%s", b); */b = "a(b(c), d(e(f, g), h(, i)))" ; //////其中不在括号中的字符表示的是根节点括号中的分别是左右儿子createBTree(&bt, b) ;if(bt != NULL)printf(" %c ", bt->data) ;printf("以广义表的形式输出：\n") ;printBTree(bt); /* 以广义表的形式输出二叉树 */printf("\n");printf("前序："); /* 前序遍历 */preOrder(bt);printf("\n");printf("中序："); /* 中序遍历 */inOrder(bt);printf("\n");printf("后序："); /* 后序遍历 */postOrder(bt);printf("\n");printf("按层："); /* 按层遍历 */levelOrder(bt);printf("\n");/* 从二叉树中查找一个元素结点 */printf("输入一个待查找的字符：\n");scanf(" %c", &x); /* 格式串中的空格跳过空白字符 */px = findBTree(bt, x);if(px){printf("查找成功：%c\n", *px);}else{printf("查找失败！\n");}printf("二叉树的深度为：");printf("%d\n", BTreeDepth(bt));clearBTree(&bt);return 0;}。