This document discusses containers like vectors and lists in C++. It provides examples of declaring and initializing vectors with different data types. Functions are demonstrated for printing, inserting, and searching elements in a vector. The document also contains examples of declaring and iterating through lists, and functions for inserting and removing elements from a list.

2. Containers
Vector
List

3.  Collections of values
 Manipulating such collections
 A class with the main purpose of holding
objects is commonly called a container

4. 01. vector<Entry> phone_book = {
02. {"David Hume",123456},
03. {"Karl Popper",234567},
04. {"Bertrand Arthur William Russell",345678}
05. };
01. void print_book(const vector<Entry>& book)
02. {
03. for (int i = 0; i!=book.size(); ++i)
04. cout << book[i] << 'n';
05. }

5. 01. void print_book(const vector<Entry>& book)
02. {
03. for (const auto& x : book) // for "auto" see §2.2.2
04. cout << x << 'n';
05. }
01. vector<int> v1 = {1, 2, 3, 4}; // size is 4
02. vector<string> v2; // size is 0
03. // size is 23; initial element value: nullptr
04. vector<Shape*> v3(23);
05. // size is 32; initial element value: 9.9
06. vector<double> v4(32,9.9);

6. 01. void input()
02. {
03. for (Entry e; cin>>e;)
04. phone_book.push_back(e);
05. }
01. vector<Entry> book2 = phone_book;

7.  vector<T>
 When you insert a new element, it’s value is
copied into the container

8. 01. void silly(vector<Entry>& book)
02. {
03. // book.size() is out of range
04. int i = book[ph.size()].number;
05. // ...
06. }
01. template<typename T>
02. class Vec : public std::vector<T> {
03. public:
04. // use the constructors from vector (under the name Vec)
05. using vector<T>::vector;
06. T& operator[](int i) // range check
07. { return vector<T>::at(i); }
08. const T& operator[](int i) const // range check const objects
09. { return vector<T>::at(i); }
10. }

9. 01. list<Entry> phone_book = {
02. {"David Hume",123456},
03. {"Karl Popper",234567},
04. {"Bertrand Arthur William Russell",345678}
05. };
01. int get_number(const string& s)
02. {
03. for (const auto& x : phone_book)
04. if (x.name==s)
05. return x.number;
06. return 0; // use 0 to represent "number not found"
07. }

10. 01. int get_number(const string& s)
02. {
03. for (auto p = phone_book.begin(); p!=phone_book.end(); ++p)
04. if (p–>name==s)
05. return p–>number;
06. return 0; // use 0 to represent "number not found"
07. }

11. 01. int get_number(const string& s)
02. {
03. for (auto p = phone_book.begin(); p!=phone_book.end(); ++p)
04. if (p–>name==s)
05. return p–>number;
06. return 0; // use 0 to represent "number not found"
07. }
01. void f(const Entry& ee, list<Entry>::iterator p
02. , list<Entry>::iterator q)
03. {
04. // add ee before the element referred to by p
05. phone_book.insert(p, ee);
06. // remove the element referred to by q
07. phone_book.erase(q);
08. }