初学者编程练习1

[2013年2月26日]

1. 编程判断两棵给定的二叉树是否相等

    Version 1 [Accepted 2013/02/27]

bool equal_bin_tree(struct binary_tree* b_tree1, struct binary_tree* b_tree2){if(b_tree1 == NULL){if(b_tree2 == NULL)  return true;else return false;}else{if((b_tree2 == NULL))  return false;else{if(b_tree1->data != b_tree2->data)    return false;else{equal_bin_tree(b_tree1->left, b_tree2->left);equal_bin_tree(b_tree1->right, b_tree2->right);}}}}

   Version 2

bool equal_bin_tree(struct binary_tree* b_tree1, struct binary_tree* b_tree2){bool ans = false;if((b_tree1 == NULL) && (b_tree2 == NULL)) return true;if((b_tree1 != NULL) && (b_tree2 != NULL)){              if(b_tree1->data == b_tree2->data)              {                        ans = equal_bin_tree(b_tree1->left, b_tree2->left);                        if(ans) ans = equal_bin_tree(b_tree1->right, b_tree2->right);              }}return ans;}

 

2. 给定一篇英语文章，提取其中的单词，并统计各个单词在文章中出现的次数

     Version 1 [Accepted 2013/03/01]

//File name: word_count.h#ifndef _WORD_COUNT_H_#define _WORD_COUNT_H_#include <stdio.h>#include <stdlib.h>#include <string.h>#define MAX_LEN 100struct word_node{int num;char word[MAX_LEN];struct word_node* next;};struct word_node* word_count(char* file_name,struct word_node* head);void eat_white_space(FILE* fp);int read_word(FILE* fp, char word[]);struct word_node*  insert_word(struct word_node* head, char word[]);void print(struct word_node* head);struct word_node* create_new_node(char word[]);void free_link(struct word_node* head);#endif

 

// File name: word_count.cpp#include "word_count.h"struct word_node* word_count(char* file_name,struct word_node* head){char  word[MAX_LEN] = {0};FILE* fp = NULL;struct word_node* new_node = NULL;head->next = NULL;if((fp = fopen(file_name, "r")) == NULL){printf("can not open the file \"%s\".\n", file_name);exit(-1);}         //打开文件 eat_white_space(fp);          //消除空白 while(!feof(fp)){read_word(fp, word);          //读取单词head = insert_word(head, word);      //插入链表eat_white_space(fp);          //消除空白}fclose(fp);return head;}void eat_white_space(FILE* fp){char ch = ' ';if (fp == NULL)    exit(0);if(!feof(fp)) {ch = fgetc(fp);while(1){if((((ch >='A') && (ch <= 'Z')) || ((ch >= 'a') && (ch <= 'z')) || ((ch >= '0') && (ch <= '9')))){   fseek(fp, -1L, SEEK_CUR);break;    //读取到的字符为字母或数字， 则eat结束，文件指针后退一位}else  {if(!feof(fp))   ch = fgetc(fp);    //读取到的字符为不为字母和数字， 且文件没有到达尾部，则继续读取下一字符else  break;    //读取到的字符为不为字母和数字， 且文件到达尾部，eat结束，}}}}int read_word(FILE* fp, char word[]){int i = 0;char ch = '*';char temp = '*';if (fp == NULL)    exit(0);while(!feof(fp)){ch = fgetc(fp);if(ch >= 'A' && ch <= 'Z')      ch = ch + 32;    //若为大写字母，则转换成小写if((ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9'))word[i++] = ch;    //若为小写字母或数字，直接写入wordelse if(ch == '-'){if(i != 0){if((temp = fgetc(fp)) == '\n')  ;    //遇到‘-’, 如果‘-’不在word的第一位，并且‘-’之后紧跟‘\n’，继续读取下一字符else if((word[i - 1] >= 'a' && word[i - 1] <= 'z') || (word[i - 1] >= '0' && word[i - 1] <= '9'))    {word[i++] = '-';                        fseek(fp, -1L, SEEK_CUR);}    // 如果‘-’不在word的第一位，并且‘-’之后紧跟数字或字母，则将‘-’写入word}}else if(ch == '\''){if(i != 0)   word[i++] = '\'';     //遇到单引号, 如果不在word的第一位，则写入word}else break;}word[i] = '\0';  //读取word完成后 写入‘\0’return 0;}struct word_node* insert_word(struct word_node* head, char word[]){int len = 0;int ans = 0;int flag = 0;struct word_node* new_node = NULL;struct word_node* p = NULL;struct word_node* p_pre = NULL;len = strlen(word);if(len > 0){if(head->next == NULL){head->next = create_new_node(word);    //head为空链表时，直接插入节点return head;}p_pre = head;p = head->next;while(p != NULL)    //比较大小，找到新节点的插入位置{ans = strcmp(word, p->word);if(ans < 0)  {flag = -1;break;}  else if(ans == 0) {flag = 0;break;}   else   {p_pre = p;p = p->next;flag = 1;}}if(flag == 0)   p->num = p->num + 1;   //flag = 0，该节点num值加一else if(flag == -1)    //flag = -1，新节点插到该节点之前{new_node = create_new_node(word);p_pre->next = new_node;new_node->next = p;}else  //flag = 1，新节点接在该节点之后{new_node = create_new_node(word);p_pre->next = new_node;}}return head;}void print(struct word_node* head){int i = 1;struct word_node* p = NULL;if(head->next != NULL){p = head->next;while(p != NULL){printf("%d.%s: %d\n", i++, p->word, p->num);p = p->next;}}}struct word_node* create_new_node(char word[]){struct word_node* new_node = NULL;if(strlen(word)){new_node = (struct word_node*) malloc(sizeof(word_node));if(new_node == NULL){printf("Out of memory!\n");exit(-1);}new_node->next = NULL;new_node->num = 1;strcpy(new_node->word, word);return new_node;}else return NULL;}void free_link(struct word_node* head){struct word_node* p = NULL;struct word_node* q = NULL;p = head;while(p != NULL){q = p->next;free(p);p = q;}}

 

// File name: main.cpp#include "word_count.h"int main(){char file_name[100] = "data.txt";    struct word_node* head = NULL;printf("Please enter the file name:   ");scanf("%s", file_name);      //输入待统计的文件名head = create_new_node("head");    //建立一个带空头节点的链表head = word_count(file_name,head);    //统计单词print(head);      //打印输出free_link(head);    //销毁链表return 0;}

 

 

代码本身的组织结构和书写风格都非常漂亮，代码近250行，达到了预期的锻炼与巩固效果。

编程过程中首次自主使用流程图来表达自己的设计意图，在方法和意识上有了质的进步。

这段代码意义重大，它已经为你成功开启了2013年的春天！

 

Version 2

// File name: main.cpp#include <iostream>#include <fstream>#include <string>#include <map>using namespace std;#define ERROR -1#define MAX_WORD_LEN 50bool is_part_of_word( char* ch ) { // 判断是否可能为一个单词的组成部分if( 'a' <= (*ch) && (*ch) <= 'z') return true;if( 'A' <= (*ch) && (*ch) <= 'Z') {*ch = 'a' + (*ch) - 'A';return true;}if('0' <= (*ch) && (*ch) <= '9') return true;if((*ch) == '-') return true;return false;}int main() {string name;fstream infile;map<string, int> record; // 使用c++内置的map数据结构map<string, int>::iterator iter;  // map的迭代结构cout << "\nPlease input the file name ==>  ";cin >> name;infile.open(name, ios::in); //以只读方式打开文件if( !infile.is_open() ) {cout << "File : "<<name<<"can not be opened for read ..."<<endl;return ERROR;}while( !infile.eof() ) {  // 是否到达文件的末尾char temp = 'a';int len = 0;char c_str[MAX_WORD_LEN + 1] = {'\0'};temp = infile.get();  // 从文件中读取一个字符while(!infile.eof() && is_part_of_word(&temp)) { // 拼接一个单词 if(len < MAX_WORD_LEN) c_str[len++] = temp;  // 防止缓冲区溢出//infile >> temp;temp = infile.get();}if(len != 0) {  // 将一个单词插入map数据结构c_str[len] = '\0';//printf("\n***%s", c_str);string word(c_str);iter = record.find(word);if( iter != record.end() ) {int counter = iter->second;iter->second = counter + 1;} else {record.insert(pair<string, int>(word, 1));}}}infile.close();int num = 0;  // 用迭代器遍历map结构中的内容for(iter = record.begin(); iter != record.end(); ++ iter) {cout << ++num << "\t" << iter->first << "\t" << iter->second << endl;}return 0;}

 

 

[2013年2月27日]

3. 打印输出采用冒泡排序算法对下列数据进行排序时的前三趟中间结果。

    数据：  7 2 4 9 1 6 8 10 11

    [Accepted 2013/03/01]

int bubble_sort(int data[], int length, int n){int i = 0;int k = 1;int j = 0;int temp = 0;int flag = 0;if(length <= 0){printf("length should be a positive number!\n");exit(-1);}if(n > length)      //若n > length，则 n 取 length 的值{printf("The max of n is %d!\n", length);n = length;}for(i = 0; i < n; i++){flag = 0;for(j = 0; j < (length - 1 - i); j++){if(data[j] > data[j + 1])     //若data[j] > data[j+1]，交换两数的值{temp = data[j];data[j] = data[j + 1];data[j + 1] = temp;flag = 1;}}print(data, length, k++);    //打印该次排序的结果if(flag == 0)    break;}while(k++ < n)print(data, length, k);return 0;}int print(int data[], int length, int k){int j = 0;printf("The %d-order is:\n", k);for(j = 0; j < length; j++){printf("%-6d", data[j]);}printf("\n");return 0;}int main(){int data[9] = {7, 2, 4, 9, 1, 6, 8, 10, 11};bubble_sort(data, 9, 11);return 0;}

完成以上3题之后，好好休息一下吧，O(∩_∩)O~

o ci ka ne sa ma ~