cout << "按作者名查找图书信息\n" << endl; cout << "请输入要查询的作者名字："; cin >> author; // 修正变量名 sql = "select * from books where books_author = '" + author + "'"; if (mysql_query(&mysql, sql.c_str())) { cout << "Error: Query[查询成功] fail." << mysql_error(&mysql) << endl; break; } res = mysql_store_result(&mysql); while ((row = mysql_fetch_row(res))) { cout << setw(5) << "编号: " << row[0] << setw(10) << "书名: " << row[1] << setw(15) << "当前数量: " << row[2] << setw(15) << "价格:￥" << row[3] << setw(10) << "作者:" << row[4] << setw(10) << "类型:" << row[5] << endl; } cout << "——————————————————————————————————————————————————————————————————————————————————————————————————————————————————\n" << endl;解释说明这段代码

C++编程：重载<<和>>操作符教程

"C++编程中<<和>>运算符的重载" 在C++编程中，为了使得自定义类的对象能够支持标准的输入输出流操作，我们需要重载<<和>>运算符。这两个运算符在I/O流库中分别用于输出（output）和输入（input）。在给定的描述...

vc++2008编译问题：从<iostream.h>到<iostream>

#include<iostream>引入了std::cout、std::cin等核心I/O流对象，它们分别用于标准输出（如屏幕）和标准输入（如键盘）。std::cout与std::endl配合可以实现文本的输出和换行，而std::cin则可以用于读取...

{ // 输入教职工信息 string name, gender, id, phone, college, department, education; cout << "请输入教职工信息：" << endl; cout << "姓名："; cin >> name; cout << "性别："; cin >> gender; cout << "工号："; cin >> id; cout << "联系电话："; cin >> phone; cout << "所在学院："; cin >> college; cout << "系："; cin >> department; cout << "学历："; cin >> education; list.addNode(Employee(name, gender, id, phone, college, department, education)); list.writeToFile();// 将数据写入文件 cout << "添加成功！" << endl; break; }解释代码

1. 提示用户输入教职工信息的各个属性，比如姓名、性别、工号等等。 2. 用户输入完信息后，创建一个 Employee 对象，将输入的信息作为参数传入。 3. 将创建的 Employee 对象添加到链表中，使用 list.addNode() ...

case 3: cout << "按作者名查找图书信息\n" << endl; cout << "请输入要查询的作者名字："; cin >> book_id; query = "select * from books where author = '" + book_author + "'"; if (mysql_query(&mysql, query.c_str())) { cout << "Error: Query[查询成功] fail." << endl; break; } res = mysql_store_result(&mysql); //查询结果集 row = mysql_fetch_row(res); cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << endl; break;为什么输入作者名字后控制台会陷入死循环

cout << "按作者名查找图书信息\n" << endl; cout << "请输入要查询的作者名字："; cin >> book_author; // 修正变量名 query = "select * from books where author = '" + book_author + "'"; if (mysql_query...

std::cout << "输入起点城市：" << endl; cin >> start; std::cout << "输入终点城市：" << endl; cin >> end; for (int i = 0; i < graph.vexnum; i++) { if (cities[i].city == start) s = i; if (cities[i].city == end) e = i; } //最短路径 system("cls"); std::cout << "读取完成" << endl; std::cout << "请选择最短路径要求" << endl; std::cout << "时间：1 " << endl; std::cout << "价格：2 " << endl; cin >> p; system("cls"); switch (p) { case 1: std::cout << "以时间为基准：" << endl; TimeShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "时间：" << D[e] << " h "; TxtWriting(graph, c, n); break; case 2: std::cout << "以价格为基准：" << endl; CostShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "价格：$" << D[e]; TxtWriting(graph, c, n); break; } return 0; } //构造控制台

1. 通过 std::cout 输出提示信息，让用户输入起点城市和终点城市。 2. 通过循环遍历 cities 数组，找到起点城市和终点城市在数组中的下标。 3. 通过 switch 语句让用户选择最短路径的要求，即以时间为基准还是以价格...

case 3: cout << "按作者名查找图书信息\n" << endl; cout << "请输入要查询的作者名字："; cin >> book_author; // 修正变量名 query = "select * from books where author = '" + book_author + "'"; if (mysql_query(&mysql, query.c_str())) { cout << "Error: Query[查询成功] fail." << endl; break; } res = mysql_store_result(&mysql); row = mysql_fetch_row(res); if (row) { // 判断查询结果是否为空 cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << endl; } else { cout << "未找到相关图书信息" << endl; } break; } break;运行后为什么没有出现图书信息而是输出Error: Query[查询成功] fail.

根据代码，出现"Error: Query[查询成功] fail."的原因可能是mysql_query()函数执行失败导致的。这可能是由于MySQL连接出现问题、查询语句错误或者权限不足导致的。您可以尝试检查以下几个方面： 1. 检查MySQL连接...

以下这段代码该怎么优化int main() { int v1=0, v2=0; std::cout << "请输入两个整数:" << std::endl; std::cout << "第一个整数:"; std::cin >> v1; std::cout << "第二个整数"; std::cin >> v2; if (v1 > v2) { int tmp = 0; tmp += v1; v1 = v2; v2 = tmp; } for (int i=v1;i <= v2;++v1) { std::cout << v1 <<std::endl; } return 0; }

std::cout << "请输入两个整数:" << std::endl; std::cout << "第一个整数:"; std::cin >> v1; std::cout << "第二个整数:"; std::cin >> v2; if (v1 > v2) { int tmp = v1; v1 = v2; v2 = tmp; } for ...

system("cls"); std::cout << "读取完成" << endl; std::cout << "请选择最短路径要求" << endl; std::cout << "时间：1 " << endl; std::cout << "价格：2 " << endl; cin >> p; system("cls"); switch (p) { case 1: std::cout << "以时间为基准：" << endl; TimeShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "时间：" << D[e] << " h "; TxtWriting(graph, c, n); case 2: std::cout << "以价格为基准：" << endl; CostShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "价格：$" << D[e]; TxtWriting(graph, c, n); }

这段代码实现了一个简单的控制台界面，让用户输入最短路径的要求（时间或价格），并调用相应的函数求解最短路径，并输出路径信息和路径花费。具体来说，该代码先清空控制台屏幕，然后输出提示信息，让用户选择最短...

int main() { int choice; do { cout << "1.增加人员信息" << endl; cout << "2.删除人员信息" << endl; cout << "3.修改人员信息" << endl; cout << "4.查找人员信息" << endl; cout << "5.保存人员信息" << endl; cout << "6.读取人员信息" << endl; cout << "0.退出系统" << endl; cout << "请输入你的choice" << endl; cin >> choice; switch (choice) { switch (choice) { case 1: { string id, name, dept, grade, group, pos; cout << "Enter student ID: "; cin >> id; cout << "Enter name: "; cin >> name; cout << "Enter department: "; cin >> dept; cout << "Enter grade: "; cin >> grade; cout << "Enter group: "; cin >> group; cout << "Enter position: "; cin >> pos; Member member(id, name, dept, grade, group, pos); team.addMember(member); cout << "Member added successfully." << endl; break; } case 2: { string id; cout << "Enter student ID to delete: "; cin >> id; team.deleteMember(id); cout << "Member deleted successfully." << endl; break; } case 3: { string id, group, position; cout << "Enter student ID to modify: "; cin >> id; cout << "Enter new group: "; cin >> group; cout << "Enter new position: "; cin >> position; team.modifyMember(id, group, position); cout << "Member modified successfully." << endl; break; } case 4: team.displayMembers(); break; case 5: team.saveToFile(); break; case 0: cout << "Exiting program." << endl; break; default: cout << "Invalid choice. Please try again." << endl; break; } } while (choice != 0); return 0; } 这段代码错误该怎么改

cout << "请输入你的choice: "; cin >> choice; switch (choice) { case 1: { string id, name, dept, grade, group, pos; cout << "Enter student ID: "; cin >> id; cout << "Enter name: "; cin >> ...

#include <iostream> #include <cstring> using namespace std; class Book { public: string title; string author; string publisher; string date; Book(string t, string a,string p,string d) { title=t; author=a; publisher=p; date=d; } ~Book(){} }; class Library { public: Book book[100]; int n; Library(){n=0;} void AddBook(Bookb) { book[n++]=b; } void DeleteBook(string t) { for (int i=0;i<n;i++) { if(book[i]->title==t) { delete book[i]; book[i]=NULL; for(int j=i;j<n-1;j++) { book[j]=book[j+1]; } n--; } } cout<<"未找到题目为"<<t<<"的书籍"<<endl; } void ShowBook() { cout<<"书籍显示"<<endl; for(int i=0;i<n;i++) { cout<<book[i]->title<<" "<<book[i]->author<<" "<<book[i]->publisher<<" "<<book[i]->date<<endl; } } BookFindBook(string t) { for (int i=0;i<n;i++) { if(book[i]->title==t) { return book[i]; } } cout<<"未找到题目为"<<t<<"的书籍"<<endl; return NULL; } ~Library() { for(int i=0;i<n;i++) { delete book[i]; } } }; int main() { Library l; int input; string t,a,p,d; cout << "------------------菜单栏------------------" << endl; cout << "1.图书信息添加" << endl; cout << "2.图书信息删除" << endl; cout << "3.图书信息查看" << endl; cout << "4.图书信息查找" << endl; cout << "0.退出" << endl; while(1) { cout << "请选择功能" << endl; cin >> input; switch (input) { case 1: { cout<<"请输入添加的图书书名："; cin>>t; cout<<"请输入添加的图书作者："; cin>>a; cout<<"请输入添加的图书出版社："; cin>>p; cout<<"请输入添加的图书出版日期："; cin>>d; Bookb=new Book(t,a,p,d); l.AddBook(b); break; } case 2: { cout<<"请输入删除的图书书名："; cin>>t; l.DeleteBook(t); break; } case 3: { l.ShowBook(); break; } case 4: { cout<<"请输入查找的图书书名："; cin>>t; Book *b=l.FindBook(t); if(b!=NULL) { cout<<"查询结果为："<<b->title<<" "<<b->author<<" "<<b->publisher<<" "<<b->date<<endl; } break; } case 0: { cout<<"已退出"<<endl; return 0; } } } }优化这段程序

cout << "查询结果为：" << b.title << "\t\t" << b.author << "\t\t" << b.publisher << "\t\t" << b.date << endl; } break; } case 0: { cout << "已退出" << endl; return 0; } default: { cout << ...

printf("|添加书籍|\n"); cout << "请输入ID:"; cin >> book_id; cout << "请输入书名:"; cin >> name; cout << "请输入数量:"; cin >> number; cout << "请输入价格:"; cin >> price; cout << "请输入作者:"; cin >> author; cout << "请输入类型:"; cin >> type; cout << "当前信息为---id=" << book_id << ",书名=" << name << ",数量=" << number << ",价格=" << price << ",作者=" << author << "类型=" << type << endl; sql = "insert into books values(" + to_string(book_id) + ",'《" + name + "》'," + to_string(number) + "," + to_string(price) + ",'" + author + "','" + type + "')"; int ret = mysql_query(&mysql, sql.c_str()); if (ret) { cout << "Error: Query[添加失败] fail." << endl; break; }详细解释下上方代码

这段代码是一个添加书籍信息的功能，主要是通过用户输入书籍的ID、书名、数量、价格、作者和类型，将这些信息插入到MySQL数据库的books表中。具体流程如下： 1. 打印"添加书籍"的提示信息。 2. 用户输入书籍的ID、...

cout << "按类型查找图书信息\n" << endl; cout << "请输入要查询的书籍类型："; cin >> type; // 修正变量名 query = "select * from books where books_type = '" + type + "'"; if (mysql_query(&mysql, query.c_str())) { cout << "Error: Query[查询成功] fail." << mysql_error(&mysql) << endl; break; } res = mysql_store_result(&mysql); row = mysql_fetch_row(res); if (row) { // 判断查询结果是否为空 cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << " 类型:" << row[5] << endl; } else { cout << "未找到相关图书信息" << endl; }为什么只输出一条数据

这段代码只输出了一条数据是因为在代码中只... cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << " 类型:" << row[5] << endl; }

cout << "按id查找图书信息\n" << endl; cout << "请输入要查询的书籍ID："; cin >> book_id; string query = "select * from books where books_id = " + to_string(book_id); if (mysql_query(&mysql, query.c_str())) { cout << "Error: Query[查询成功] fail." << endl; break; } res = mysql_store_result(&mysql); //查询结果集 row = mysql_fetch_row(res); cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << endl; break; }将这段c++代码更改为根据作者来查询图书信息

可以将原来的查询语句中的 books_id 改为 author，即： ...cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << endl;

void showCourseList() { cout << "---------------------" << endl; cout << "课程列表：" << endl; for (size_t i = 0; i < courses.size(); i++) { cout << i + 1 << ". " << courses[i].name << "（编号：" << courses[i].code << "，地点：" << courses[i].location << "，学分：" << courses[i].credit << "）" << endl; } cout << "---------------------" << endl; } // 增加课程 void addCourse() { Course course; cout << "请输入课程名称：" << endl; cin >> course.name; cout << "请输入课程编号：" << endl; cin >> course.code; cout << "请输入上课地点：" << endl; cin >> course.location; cout << "请输入学分：" << endl; cin >> course.credit; courses.push_back(course); cout << "课程添加成功！" << endl; } // 管理员登录 void adminLogin() { string id, password; cout << "请输入管理员账号：" << endl; cin >> id; cout << "请输入密码：" << endl; cin >> password; if (id == ADMIN_ID && password == ADMIN_PASSWORD) { // 登录成功，进入管理员菜单 int choice; do { adminMenu(); cin >> choice; switch (choice) { case 1: // 查看课程列表 showCourseList(); break; case 2: // 增加课程 addCourse(); break; case 0: // 退出 break; default: cout << "无效的选择，请重新输入！" << endl; break; } } while (choice != 0); } else { cout << "管理员账号或密码错误，请重新登录！" << endl; } }

这段代码是关于一个课程管理系统的，其中包括三个函数：showCourseList、add...管理员登录需要输入账号和密码，如果输入正确则可以进入管理员菜单，管理员菜单包括查看课程列表和增加课程两个选项，还可以选择退出。

void LookupNum(Student stu[]) { system("cls"); int n = Read(stu); int s; int i = 0; cout << endl << "======>> 查找学生成绩 <<======" << endl; cout << "请输入要查找学生的学号："; cin >> s; while ((stu[i].num - s) != 0 && i < n)i++; if (i == n) { cout << "======>> 对不起，无法找到该学生...... <<======" << endl; } else { cout << "----------------------------" << endl; cout << "班级：" << stu[i].class_0 << endl; cout << "学号：" << stu[i].num << endl; cout << "姓名：" << stu[i].name << endl; cout << "电子技术：" << stu[i].elec << endl; cout << "C++程序设计：" << stu[i].c_program << endl; cout << "多媒体技术：" << stu[i].media << endl; cout << "大学英语：" << stu[i].english << endl; cout << "高等数学：" << stu[i].math << endl; cout << "大学体育：" << stu[i].sport << endl; cout << "马克思主义基本原理：" << stu[i].polity << endl; cout << "平均分：" << stu[i].average << endl; cout << "总分：" << stu[i].total << endl; } }修改为折半查找

cout << "请输入要查找学生的学号："; cin >> s; // 先对stu数组按学号升序排序 sort(stu, stu + n, [](const Student& a, const Student& b) { return a.num < b.num; }); // 二分查找目标学号 int left = 0,...

void Input(STU stu[]) { char date[15]; string stuN, ClassN; int stuID, ClassX, ClassL; while (1) { cout << "请输入记录情况个数" << endl; cin >> n; for (int i = 0; i < n; i++) { cout << "请输入第" <> date; cout << "请输入第几节课\n"; cin >> ClassX; cout << "请输入课程名称\n"; cin >> ClassN; cout << "请输入学生姓名\n"; cin >> stuN; cout << "请输入学生学号\n"; cin >> stuID; cout << "请输入缺课类型，1代表请假，2代表旷课, 3代表迟到\n"; cin >> ClassL; stu[i].input(date, ClassX, ClassN, stuN, stuID, ClassL); } cout << "输入信息完毕！是否继续输入？y是继续，n是停止：" << endl; char cc; getchar(); cin >> cc; if (cc == 'n') return; } }

在每一轮循环中，先输入缺课记录的个数 n，然后依次输入每个学生的缺课信息，包括缺课日期、课节、课程名称、学生姓名、学生学号和缺课类型。在输入缺课信息时，使用了 STU 类中的 input 函数，将输入的信息存储到...

cout << cin >> a >> b; cout << <<< endl;

这个代码片段是用C++语言编写的。它使用了输入输出流和流提取运算符。具体来说，cout表示标准输出流，cin...1234

list<Book>lst; class Bookstore { private: list<Book> books; public: void WarehousingBook() {//入库书籍 cout << "请输入书名："; string name; cin >> name; cout << "请输入作者："; string author; cin >> author; cout << "请输入出版社："; string publisher; cin >> publisher; cout << "请输入页数："; int pages; cin >> pages; cout << "请输入最新入库时间（格式：年月日）："; int year, month, day; cin >> year >> month >> day; Time latestTime(year, month, day); cout << "请输入进货数量："; int stock; cin >> stock; cout << "请输入价格："; double price; cin >> price; list<Book>::iterator it; for (it = lst.begin(); it != lst.end(); it++){ if (it->name == name && it->author == author) { it->stock += stock; cout << "该书库里存在该书，入库成功！" << endl; return; } } Book b(name, author, publisher, pages, latestTime, stock, price); books.push_back(b); cout << "该书库里未存在该书，入库成功！" << endl; } 为什么实现不了

cout << "请输入作者："; string author; cin >> author; cout << "请输入出版社："; string publisher; cin >> publisher; cout << "请输入页数："; int pages; cin >> pages; cout << "请输入最新入库...

优化这段代码 int n; cout <<"输入数组长度：" << endl; cin >> n; cout <<"请输入数组：" << endl; int nums[n]; for(int i=0;i<n;i++) { cin >> nums[n]; } shunxuSort(nums); for (int num : nums) { cout <<"顺序排序的结果"<< num << " "; } cout << endl; zhebanSort(nums); for (int num : nums) { cout <<"折半排序的结果："<< num << " "; } cout << endl; maopaoSort(nums); for (int num : nums) { cout <<"冒泡排序的结果："<< num << " "; } cout << endl; return 0; }

cout << "请输入数组：" << endl; for (int i = 0; i < n; i++) { cin >> nums[i]; } shunxuSort(nums); cout << "顺序排序的结果："; for (int i = 0; i < n; i++) { cout << nums[i] << " "; } cout << endl; ...

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