3.11 封装集合

【1】封装集合

范例：

  1 #include <QString>
  2 #define MAX_STUDENT_COUNT 20
  3 
  4 class Student
  5 {
  6 public:
  7     Student(int nId, QString name = QString(), QString department = QString("jisuanji"))
  8         : m_nID(nId)
  9         , m_name(name)
 10         , m_department(department)
 11     {}
 12 
 13     int getId() const
 14     {
 15         return m_nID;
 16     }
 17     void setId(int nId)
 18     {
 19         m_nID = nId;
 20     }
 21     QString getName() const
 22     {
 23         return m_name;
 24     }
 25     void setName(QString name)
 26     {
 27         m_name = name;
 28     }
 29     QString getDepartment() const
 30     {
 31         return m_department;
 32     }
 33     void setDepartment(QString department)
 34     {
 35         m_department = department;
 36     }
 37 
 38     bool operator ==(const Student& student) const
 39     {
 40         return (student.getId() == m_nID &&
 41                 student.getName() == m_name &&
 42                 student.getDepartment() == m_department);
 43     }
 44 
 45 private:
 46     int m_nID;
 47     QString m_name;
 48     QString m_department;
 49 };
 50 
 51 class School
 52 {
 53 public:
 54     School()
 55     {
 56         for (int i = 1; i < MAX_STUDENT_COUNT + 1; ++i)
 57         {
 58             m_students.append(*(new Student(i)));
 59         }
 60     }
 61 
 62     // 获取到的仅仅只是一个副本
 63     const QList<Student> getStudents()
 64     {
 65         return m_students;
 66     }
 67 
 68     void addStudent(Student student)
 69     {
 70         m_students.append(student);
 71     }
 72 
 73     void removeStudent(int nId)
 74     {
 75         QList<Student>::const_iterator cIter = m_students.cbegin();
 76         while (cIter != m_students.cend())
 77         {
 78             if ((*cIter).getId() == nId)
 79             {
 80                 m_students.removeOne(*cIter);
 81                 return;
 82             }
 83             ++cIter;
 84         }
 85     }
 86 
 87 private:
 88     QList<Student> m_students; // 集合
 89 };
 90 
 91 /*
 92  * 有个函数返回一个集合。让这个函数返回该集合的一个只读副本，并在这个类中提供添加/移除集合元素的函数。
 93  */
 94 
 95 void main()
 96 {
 97     School school;
 98     QList<Student> studentList = school.getStudents();
 99     Student student(22, "liu", "math");
100     school.addStudent(student);
101     school.removeStudent(12);
102 }