用C++写可视化界面的图书馆管理系统

下面是一个使用Qt库实现的简单图书馆管理系统的示例代码，其中包括添加、删除、更新和搜索书籍的功能：

#include <QtWidgets/QApplication>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QWidget>
#include <QtWidgets/QLabel>
#include <QtWidgets/QLineEdit>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QComboBox>
#include <QtWidgets/QMessageBox>
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlQuery>

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr)
        : QMainWindow(parent)
    {
        // 创建窗口控件
        QWidget *centralWidget = new QWidget(this);
        QLabel *titleLabel = new QLabel(tr("图书馆管理系统"), centralWidget);
        QLabel *nameLabel = new QLabel(tr("书名:"), centralWidget);
        QLabel *authorLabel = new QLabel(tr("作者:"), centralWidget);
        QLineEdit *nameEdit = new QLineEdit(centralWidget);
        QLineEdit *authorEdit = new QLineEdit(centralWidget);
        QPushButton *addButton = new QPushButton(tr("添加"), centralWidget);
        QPushButton *deleteButton = new QPushButton(tr("删除"), centralWidget);
        QPushButton *updateButton = new QPushButton(tr("更新"), centralWidget);
        QPushButton *searchButton = new QPushButton(tr("搜索"), centralWidget);
        QComboBox *bookList = new QComboBox(centralWidget);

        // 设置窗口控件位置和大小
        titleLabel->setGeometry(QRect(150, 20, 100, 30));
        nameLabel->setGeometry(QRect(20, 70, 50, 30));
        nameEdit->setGeometry(QRect(80, 70, 150, 30));
        authorLabel->setGeometry(QRect(20, 120, 50, 30));
        authorEdit->setGeometry(QRect(80, 120, 150, 30));
        addButton->setGeometry(QRect(20, 170, 70, 30));
        deleteButton->setGeometry(QRect(100, 170, 70, 30));
        updateButton->setGeometry(QRect(180, 170, 70, 30));
        searchButton->setGeometry(QRect(260, 170, 70, 30));
        bookList->setGeometry(QRect(20, 220, 310, 30));

        // 设置窗口标题和大小
        setWindowTitle(tr("图书馆管理系统"));
        setCentralWidget(centralWidget);
        setFixedSize(350, 280);

        // 连接数据库
        QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
        db.setDatabaseName("library.db");
        if (!db.open()) {
            QMessageBox::critical(this, tr("错误"), tr("无法连接数据库!"));
            return;
        }

        // 创建书籍表
        QSqlQuery query;
        if (!query.exec("CREATE TABLE IF NOT EXISTS books (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, author TEXT)")) {
            QMessageBox::critical(this, tr("错误"), tr("无法创建书籍表!"));
            return;
        }

        // 添加书籍
        connect(addButton, &QPushButton::clicked, [=]() {
            QString name = nameEdit->text().trimmed();
            QString author = authorEdit->text().trimmed();
            if (name.isEmpty() || author.isEmpty()) {
                QMessageBox::warning(this, tr("警告"), tr("书名和作者不能为空!"));
                return;
            }
            query.prepare("INSERT INTO books (name, author) VALUES (:name, :author)");
            query.bindValue(":name", name);
            query.bindValue(":author", author);
            if (!query.exec()) {
                QMessageBox::critical(this, tr("错误"), tr("无法添加书籍!"));
                return;
            }
            nameEdit->clear();
            authorEdit->clear();
            bookList->addItem(name);
        });

        // 删除书籍
        connect(deleteButton, &QPushButton::clicked, [=]() {
            QString name = bookList->currentText();
            if (name.isEmpty()) {
                QMessageBox::warning(this, tr("警告"), tr("请选择要删除的书籍!"));
                return;
            }
            int index = bookList->currentIndex();
            bookList->removeItem(index);
            query.prepare("DELETE FROM books WHERE name = :name");
            query.bindValue(":name", name);
            if (!query.exec()) {
                QMessageBox::critical(this, tr("错误"), tr("无法删除书籍!"));
                return;
            }
            nameEdit->clear();
            authorEdit->clear();
        });

        // 更新书籍
        connect(updateButton, &QPushButton::clicked, [=]() {
            QString name = bookList->currentText();
            QString author = authorEdit->text().trimmed();
            if (name.isEmpty()) {
                QMessageBox::warning(this, tr("警告"), tr("请选择要更新的书籍!"));
                return;
            }
            if (author.isEmpty()) {
                QMessageBox::warning(this, tr("警告"), tr("作者不能为空!"));
                return;
            }
            query.prepare("UPDATE books SET author = :author WHERE name = :name");
            query.bindValue(":name", name);
            query.bindValue(":author", author);
            if (!query.exec()) {
                QMessageBox::critical(this, tr("错误"), tr("无法更新书籍!"));
                return;
            }
            authorEdit->clear();
        });

        // 搜索书籍
        connect(searchButton, &QPushButton::clicked, [=]() {
            QString keyword = nameEdit->text().trimmed();
            if (keyword.isEmpty()) {
                QMessageBox::warning(this, tr("警告"), tr("关键字不能为空!"));
                return;
            }
            bookList->clear();
            query.prepare("SELECT name FROM books WHERE name LIKE :keyword");
            query.bindValue(":keyword", "%" + keyword + "%");
            if (!query.exec()) {
                QMessageBox::critical(this, tr("错误"), tr("无法搜索书籍!"));
                return;
            }
            while (query.next()) {
                bookList->addItem(query.value(0).toString());
            }
        });
    }
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MainWindow window;
    window.show();
    return app.exec();
}

此示例代码使用Qt库创建了一个包含添加、删除、更新和搜索书籍的简单图书馆管理系统。在此示例代码中，我们使用了Qt的GUI组件和QtSql库来连接SQLite数据库并执行SQL查询。