C++如何实现命令行通讯录查询

Struct Contact

struct Contact {     std::String name;     std::string phone;     std::string email; // 也可以有更多字段，比如地址、备注等      // 方便打印的函数     void display() const {         std::cout << "姓名: " << name << ", 电话: " << phone << ", 邮箱: " << email << std::endl;     }      // 用于文件读写的序列化/反序列化辅助函数     // 假设以逗号分隔     std::string serialize() const {         return name + "," + phone + "," + email;     }      static Contact deserialize(const std::string& line) {         Contact c;         size_t pos1 = line.find(',');         size_t pos2 = line.find(',', pos1 + 1);          if (pos1 != std::string::npos && pos2 != std::string::npos) {             c.name = line.substr(0, pos1);             c.phone = line.substr(pos1 + 1, pos2 - (pos1 + 1));             c.email = line.substr(pos2 + 1);         } else {             // 处理格式错误或不完整的情况，这里简单地赋空             c.name = line; // 至少保留一部分信息             c.phone = "";             c.email = "";         }         return c;     } };

std::vector<Contact> contacts; // 存储所有联系人

std::map<std::string, Contact>

std::unordered_map<std::string, Contact>

std::map

bool running = true; while (running) {     displayMenu();     // 获取并处理用户输入     // ... }

is_open()

std::cerr

std::cout

loadContactsFromFile

saveContactsToFile

#include <iostream> #include <vector> #include <string> #include <fstream> #include <limits> // For numeric_limits  // Contact 结构体定义 struct Contact {     std::string name;     std::string phone;     std::string email;      void display() const {         std::cout << "姓名: " << name << ", 电话: " << phone << ", 邮箱: " << email << std::endl;     }      std::string serialize() const {         // 简单地用逗号分隔，如果字段本身包含逗号，这里需要更复杂的转义逻辑         return name + "," + phone + "," + email;     }      static Contact deserialize(const std::string& line) {         Contact c;         size_t pos1 = line.find(',');         size_t pos2 = line.find(',', pos1 + 1);          if (pos1 != std::string::npos && pos2 != std::string::npos) {             c.name = line.substr(0, pos1);             c.phone = line.substr(pos1 + 1, pos2 - (pos1 + 1));             c.email = line.substr(pos2 + 1);         } else if (pos1 != std::string::npos) { // 只有姓名和电话             c.name = line.substr(0, pos1);             c.phone = line.substr(pos1 + 1);             c.email = "";         } else { // 只有姓名             c.name = line;             c.phone = "";             c.email = "";         }         return c;     } };  // 全局的联系人列表 std::vector<Contact> contacts; const std::string FILENAME = "contacts.txt"; // 数据文件  // 函数声明 void displayMenu(); void addContact(); void searchContact(); void listAllContacts(); void saveContactsToFile(); void loadContactsFromFile();  int main() {     loadContactsFromFile(); // 程序启动时加载数据      bool running = true;     while (running) {         displayMenu();         std::cout << "请输入您的选择: ";         std::string choice_str;         std::getline(std::cin >> std::ws, choice_str); // 使用 >> std::ws 跳过前一个换行符          try {             int choice = std::stoi(choice_str);             switch (choice) {                 case 1: addContact(); break;                 case 2: searchContact(); break;                 case 3: listAllContacts(); break;                 case 4:                     saveContactsToFile();                     running = false;                     std::cout << "程序已退出。再见！n";                     break;                 default:                     std::cout << "无效的选择，请重新输入。n";                     break;             }         } catch (const std::invalid_argument& e) {             std::cerr << "输入无效，请确保输入的是数字。n";         } catch (const std::out_of_range& e) {             std::cerr << "输入的数字太大或太小，请重新输入。n";         }         std::cout << std::endl; // 每次操作后换行，美观     }      return 0; }  void displayMenu() {     std::cout << "--- 通讯录管理系统 ---n";     std::cout << "1. 添加联系人n";     std::cout << "2. 查询联系人n";     std::cout << "3. 列出所有联系人n";     std::cout << "4. 保存并退出n"; }  void addContact() {     Contact newContact;     std::cout << "请输入姓名: ";     std::getline(std::cin >> std::ws, newContact.name);     std::cout << "请输入电话: ";     std::getline(std::cin >> std::ws, newContact.phone);     std::cout << "请输入邮箱 (可选，留空请直接回车): ";     std::getline(std::cin >> std::ws, newContact.email); // 允许为空      // 简单验证，确保姓名不为空     if (newContact.name.empty()) {         std::cout << "姓名不能为空，添加失败。n";         return;     }      contacts.push_back(newContact);     std::cout << "联系人 '" << newContact.name << "' 添加成功！n"; }  void searchContact() {     std::cout << "请输入要查询的姓名或电话 (支持模糊查询): ";     std::string query;     std::getline(std::cin >> std::ws, query);      bool found = false;     for (const auto& contact : contacts) {         // 简单的模糊查询，判断姓名或电话是否包含查询字符串         if (contact.name.find(query) != std::string::npos ||             contact.phone.find(query) != std::string::npos) {             contact.display();             found = true;         }     }      if (!found) {         std::cout << "未找到匹配的联系人。n";     } }  void listAllContacts() {     if (contacts.empty()) {         std::cout << "通讯录为空。n";         return;     }     std::cout << "--- 所有联系人 ---n";     for (const auto& contact : contacts) {         contact.display();     }     std::cout << "-------------------n"; }  void saveContactsToFile() {     std::ofstream outFile(FILENAME);     if (!outFile.is_open()) {         std::cerr << "错误: 无法打开文件 " << FILENAME << " 进行写入。n";         return;     }     for (const auto& contact : contacts) {         outFile << contact.serialize() << std::endl;     }     outFile.close();     std::cout << "通讯录已保存到 " << FILENAME << "。n"; }  void loadContactsFromFile() {     std::ifstream inFile(FILENAME);     if (!inFile.is_open()) {         std::cerr << "注意: 无法打开文件 " << FILENAME << "，将创建一个新的通讯录。n";         return; // 返回空向量，表示从头开始     }     std::string line;     while (std::getline(inFile, line)) {         if (!line.empty()) {             contacts.push_back(Contact::deserialize(line));         }     }     inFile.close();     std::cout << "已从 " << FILENAME << " 加载通讯录。n"; }