This document discusses abstract data types and containers in C++. It defines an abstract Container class with pure virtual functions for accessing elements and size. It then shows two classes, Vector_container and List_container, that implement the Container interface to allow a function to generically use different container types.

2. Abstract Types
Containers
Virtual Function

3. ‫جداسازی‬Representation‫از‬Definition
‫جداسازی‬Interface‫از‬Implementation
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4. 01. class Container {
02. public:
03. virtual double& operator[](int) = 0;// Pure virtual
04. virtual int size() const = 0;// const member function
05. virtual ~Container() {} // Destructor
06. };

5. 01. void use(Container& c)
02. {
03. const int sz = c.size();
04. for (int i = 0; i != sz; ++i)
05. cout << c[i] << 'n';
06. }
01. class Container {
02. public:
03. virtual double& operator[](int) = 0;// Pure virtual
04. virtual int size() const = 0;// const member function
05. virtual ~Container() {} // Destructor
06. };

6. 01. // Vector_container implements Container
02. class Vector_container : public Container {
03. Vector v;
04. public:
05. Vector_container(int s) : v(s) {}// Vector of s elements
06. ~Vector_container() {}
07.
08. double& operator[](int i) { return v[i]; }
09. int size() const { return v.size(); }
10. };

7. 01. // Vector_container implements Container
02. class Vector_container : public Container {
03. Vector v;
04. public:
05. Vector_container(int s) : v(s) {}// Vector of s elements
06. ~Vector_container() {}
07.
08. double& operator[](int i) { return v[i]; }
09. int size() const { return v.size(); }
10. };
01. void g()
02. {
03. Vector_container vc {10,9,8,7,6,5,4,3,2,1,0};
04. use(vc);
05. }

8. 01. // List_container implements Container
02. class List_container : public Container {
03. std::list<double> ld; // list of doubles
04. public:
05. List_container() {} // Empty list
06. List_container(initilizer_list<double> il) : ld{il} {}
07. ~List_container() {}
08. double& operator[](int i);
09. int size() const { return ld.size(); }
10. };

9. 01. double& List_container:: operator[](int i)
02. {
03. for (auto& x : ld) {
04. if (i == 0) return x;
05. --i;
06. }
07. throw out_of_range("List container");
08. }
01. void h()
02. {
03. List_container lc = { 1,2,3,4,5,6,7,8,9 };
04. use(lc);
05. }

10. 01. void use(Container& c)
02. {
03. const int sz = c.size();
04. for (int i = 0; i != sz; ++i)
05. cout << c[i] << 'n';
06. }