信号槽其他操作：

关联信号槽：

//信号关联信号
    void(teacher::*teacherSingler2)(void) = &teacher::hungry;
    void(student::*studentSlot2)(void) = &student::eat;
    connect(teh,teacherSingler2,stu,studentSlot2);
    connect(btn,&QPushButton::clicked,teh,teacherSingler2);

断开信号槽：

//断开信号
    disconnect(btn,&QPushButton::clicked,teh,teacherSingler2);