void login::on_pushButton_clicked() { QString username = ui->usernameLineEdit->text(); QString password = ui->passwordLineEdit->text(); if (username == "admin" && password == "admin") { QMessageBox::information(this, tr("提示"), tr("登录成功！")); // 登录成功，跳转到主界面 MainWidget *mainWidget = new MainWidget; mainWidget->show(); this->close(); } else { QMessageBox::warning(this, tr("警告"), tr("用户名或密码错误！")); // 登录失败，清空输入框 ui->usernameLineEdit->clear(); ui->passwordLineEdit->clear(); ui->usernameLineEdit->setFocus(); } }与 toolBtn1 = new QToolButton; toolBtn1->setText(tr("道枝小尧")); toolBtn1->setIcon(QPixmap(":/image/spqy.png")); toolBtn1->setIconSize(QPixmap(":/image/spqy.png").size()); toolBtn1->setAutoRaise(true); toolBtn1->setToolButtonStyle(Qt::ToolButtonTextBesideIcon); connect(toolBtn1, SIGNAL(clicked()), this, SLOT(showChatWidget1()));可以联系起来

printf("请输入学生数量：");
scanf("%d", &student_count);

printf("请输入科目数量：");
scanf("%d", &course_count);

int choice;
do {
show_menu();
scanf("%d", &choice);

switch这两段代码没有直接关联，它们分别是不同的功能实现。第一段代码实现的 (choice) {
case 1:
add_student();
break;
case 2:
modify_student();
break;
是一个简单的登录功能，当用户名和密码正确时，跳转到主界面；否则弹出警告提示 case 3:
delete_student();
break;
case 4:
show_all_students();
break;
case 框。第二段代码则是创建了一个QToolButton对象，并且设置了按钮的文本、图标、样式5:
insert_student();
break;
case 6:
search_student();
break;
case 7:
sort等属性，并且连接了按钮的clicked()信号到槽函数showChatWidget1()。它们之间并没有明显的联系。