C++介面與實現的抽象分離
摘要：
IPerson.h
1 #ifndef I_PERSON_H_
2 #define I_PERSON_H_
3
4 #include <string>
5 #include <ostream>
6 class IPerson
7 {
8 publ...
IPerson.h
1 #ifndef I_PERSON_H_
2 #define I_PERSON_H_
3
4 #include <string>
5 #include <ostream>
6 class IPerson
7 {
8 public:
9virtual std::string GetName() const = 0;
10virtual int GetAge() const = 0;
11virtual std::string GetClassName() const = 0;
12 };
13
14 std::ostream& operator<<(std::ostream &os, const IPerson &person);
15
16 #endif
Person.h
1 #ifndef PERSON_H_
2 #define PERSON_H_
3
4 #include "IPerson.h"
5
6 class Person : virtual public IPerson
7 {
8 public:
9Person(const std::string &name, const int age);
10virtual ~Person();
11std::string GetName() const override;
12int GetAge() const override;
13std::string GetClassName() const override;
14 private:
15std::string name;
16int age;
17 };
18
19 #endif
Person.cpp
1 #include "Person.h"
2
3 Person::Person(const std::string &name, const int age) :
4name(name),
5age(age)
6 {
7 }
8
9 Person::~Person()
10 {
11 }
12
13 std::string Person::GetName() const
14 {
15return name;
16 }
17
18 int Person::GetAge() const
19 {
20return age;
21 }
22
23 std::string Person::GetClassName() const
24 {
25return std::string("Person");
26 }
27
28 std::ostream& operator<<(std::ostream &os, const IPerson &person)
29 {
30os << "Name: " << person.GetName() << ", "
31<< "Age: " << person.GetAge() << ", ";
32
33return os;
34 }
IStudent.h
1 #ifndef I_STUDENT_H_
2 #define I_STUDENT_H_
3
4 #include "IPerson.h"
5
7
8 class IStudent : virtual public IPerson
9 {
10 public:
11virtual int GetGrade() const = 0;
12 };
13
14 std::ostream& operator<<(std::ostream &os, const IStudent &student);
15
16 #endif
Student.h
1 #ifndef STUDENT_H_
2 #define STUDENT_H_
3
4 #include "IStudent.h"
5 #include "Person.h"
6
7 class Student : virtual public IStudent, public Person
8 {
9 public:
10Student(const std::string &name, const int age, const int grade);
11~Student();
12
13int GetGrade() const override;
14std::string GetClassName() const override;
15 private:
16int grade;
17 };
18
19 #endif
Student.cpp
1 #include "Student.h"
2
3 Student::Student(const std::string &name, const int age, const int grade) :
4Person(name, age),
5grade(grade)
6 {
7 }
8
9 Student::~Student()
10 {
11 }
12
13 int Student::GetGrade() const
14 {
15return grade;
16 }
17
18 std::string Student::GetClassName() const
19 {
20return std::string("Student");
21 }
22
23 std::ostream& operator<<(std::ostream &os, const IStudent &student)
24 {
25const IPerson &person = student;
26os << person;
27os << "Grade: " << student.GetGrade() << ", ";
28
29return os;
30 }
main.cpp
1 #include <iostream>
2 #include "Student.h"
3
4 using namespace std;
5
6 int main()
7 {
8Student student(string("Leon"), 14, 8);
9cout << "Student: " << student << endl;
10
11IStudent &iStudent = student;
12cout << "IStudent: " << iStudent << endl;
13cout << "ClassName: " << iStudent.GetClassName() << endl;
14
15IPerson &iPerson = student;
16cout << "IPerson: " << iPerson << endl;
17cout << "ClassName: " << iPerson.GetClassName() << endl;
18
19cout << sizeof(IPerson) << endl;
20cout << sizeof(Person) << endl;
21cout << sizeof(IStudent) << endl;
22cout << sizeof(Student) << endl;
23
24return 0;
25 }
測試結果
Student: Name: Leon, Age: 14, Grade: 8,
IStudent: Name: Leon, Age: 14, Grade: 8,
ClassName: Student
IPerson: Name: Leon, Age: 14,
ClassName: Student
4
48
12
64