Copyright © 2006 Pearson Addison-Wesley. All rights reserved. 13-1 Today’s Learning Objective ...

Copyright © 2006 Pearson Addison-Wesley. All rights reserved. 13-1

Today’s Learning Objective Standard Template Library


Standard Template Library Recall array and linkedlist structures

Standard Template Library (STL) Includes libraries for all such data structures

Each data structure in STL contains Containers: Like data structures Iterators: Like pointers


Containers Container classes in STL

Each is template class with parameter for particular data type to be stored

e.g., Lists of int

Each has own iterator


Different Containers Sequential

1st element, next element, … to last element

Examples: vector, linked list

Associative Example: set and map


Iterators Generalization of a pointer

Typically even implemented with pointer Designed to hide details of implementation Provide uniform interface across different

container classes

Each container class has "own" iterator type Similar to how each data type has own

pointer type


Manipulating Iterators overloaded operators:

++, --, ==, != *

So if p is iterator variable, *p gives access to datapointed to by p

Vector container has members begin() and end()

c.begin(); //Returns iterator for 1st item in cc.end(); //Returns "test" value for end


Cycling with Iterators

Cycling ability (c is a container; p is a iterator):

for (p=c.begin(); p!=c.end(); p++){

//process *p //*p is current data item

}


Vector

Container: vector<int> container;

Iterator: vector<int>::iterator p;

Difference between vector and array Array size is fixed, while vector size is

flexible

Example: Iterators Used with a Vector (1 of 2)

#include <iostream>#include <vector>using std::cout;using std::endl;using std::vector;

int main( ){

vector<int> container;

for (int i = 1; i <= 4; i++)container.push_back(i);

cout << "Here is what is in the container:\n";vector<int>::iterator p;for (p = container.begin( ); p != container.end( ); p++)

cout << *p << " ";cout << endl;

Example: Iterators Used with a Vector (2 of 2)

cout << "Setting entries to 0:\n"; for (p = container.begin( ); p != container.end( ); p++) *p = 0; cout << "Container now contains:\n";for (p = container.begin( ); p !=container.end( ); p++) cout << *p << " ";cout << endl;

return 0;}

Here is what is in the container:1 2 3 4Setting entries to 0:Container now contains:0 0 0 0


Random Access of vector iterators


List Container:

list<int> container;

Iterator: list<int>::iterator p;

Difference between vector and list Vector allows random access while list do

not allow


Display 19.4 Two Kinds of Lists

STL list is a double link list

Using the list Container(1 of 2)#include <iostream>#include <list>using std::cout;using std::endl;using std::list;

int main( ){

list<int> LO;for (int i = 1; i <= 3; i++){

LO.push_back(i);LO.push_front(i);

}

cout << "List contains:\n";list<int>::iterator iter;for (iter = LO.begin(); iter != LO.end(); iter++)

cout << *iter << " ";cout << endl;

Using the list Container(2 of 2)cout << "Setting all entries to 0:\n";for (iter = LO.begin(); iter != LO.end(); iter++)

*iter = 0;

cout << "List now contains:\n";for (iter = LO.begin(); iter != LO.end(); iter++)

cout << *iter << " ";cout << endl;

return 0;}

List contains:3 2 1 1 2 3Setting all entries to 0:List now contains:0 0 0 0 0 0


Set Container Stores elements without repetition

1st insertion places element in set

Each element value is its own key

Capabilities: Add elements Delete elements Ask if element is in set

Set Container example (1)#include <iostream>#include <set>using std::set;using std::cout;using std::endl;using std::set<char>::iterator;

int main(){

set<char> s;iterator p;

s.insert('A');s.insert('D');s.insert('D');s.insert('C');s.insert('C');s.insert('B');


Set Container example(2)cout << “The set contains:\n";

for (p=s.begin(); p!=s.end();p++)cout << *p << "\t";

cout << endl;

s.erase('C');

cout << “The Set contains:\n";for (p=s.begin(); p!=s.end();p++){

cout << *p << "\t";}cout << endl;return 1;

}


The set contains:A B C DRemoving C:The Set containsA B D


map Template Class Stores pairs of data

<key type, value type> Examples:

<SSN, Student GPA> <Course Number, Course Name>

The first data (key type) is its key

Capabilities: Add elements Delete elements Ask if element is in map

Date post:	08-Jan-2018
Category:	Documents
Upload:	gwenda-grant
View:	215 times
Download:	1 times

Copyright © 2006 Pearson Addison-Wesley. All rights reserved. 13-1 Today’s Learning Objective ...

Documents