15. STL - Data Structures using C++ by Varsha Patil

1Oxford University Press © 2012

Data Structures Using C++ by Dr Varsha Patil

15. Standard Template Library (STL)



Objectives

Abstract data type (ADT) implementation in C++ and rationale for using them

How ADTs aid code reuse Five components of standard template

library (STL) and their power Simplify task of writing application

codes with the use of STL



Introduction The STL is a part of the standard C++

class library and can be used as the standard approach for storing and processing data



A data type consists of a collection of values together with a set of basic operations defined on these values

A data type is called an ADT if a programmer can use it without having access to and also without knowing the details of how the values and operations are implemented

Abstract Data Type



The term ADT describes a comprehensive collection of data values and operations

The term data structure refers to the study of data and how to represent data object within a program, that is, the implementation of structured relationship

Abstract Data Type and Data Structures



ADT stack(element)Declare create() → stackpop(push(e,S)) = SgetTop(stack) → elementis_empty(stack) → Boolean;is_empty(create) = truepop(stack) → stackfor all S Î stack, e Î element,

is_empty(push(e, S)) = falsepop(create()) = errorpush(element, stack) → stack

Stack Abstract Data Type



A Survey of Programming

Object-oriented Programming

Techniques



Unstructured programmingProcedural programmingModular programmingObject-oriented programming

A Survey of Programming



Unstructured programming: the main program directly operates on global data

Unstructured programming

ProgramPROGRAM

MAIN PROGRAM DATA



With procedural programming, we are able to combine returning sequences of statements into one single place

A procedure call is used to invoke the procedure

Procedural Programming



Execution of procedures: after processing, flow of controls proceed where the call was made


Main program Procedure



Procedural programming: the main program coordinates calls to procedures and hands over appropriate data as parameters


ProgramPROGRAM

MAIN PROGRAM DATA

PROCEDURE1

PROCEDURE2

PROCEDURE3



Modular programming

Program

Main program data

Module1 data+data1

Module2 data+dat2

Procedure1

Procedure2

Procedure3



Object-oriented programming: objects of the program interact by sending messages to each other


ProgramObject1

dataObject4data

Object3 data

Object2 data




Object-oriented programming is a method of implementation in which

Objects are the fundamental building blocks Each object is an instance of some type (specification or class)

Objects can interact with each other Classes are related to each other by inheritance relationship




An object-oriented language is the one that supports objects, and programs divided into objects,

contains objects belonging to a class, supports inheritance



Objects Classes Data abstraction and encapsulation Inheritance Reusability Polymerisation Dynamic binding Message passing

Basic Concepts of Object-oriented Programming



Objects Objects are the basic runtime entities in an

object- oriented system Programming problem is analyzed in terms of

objects and the nature of communication between them

Each object contains data and code to manipulate the data



Object-oriented programming encapsulates data (attributes) and functions (behaviour) into package called as classes

A class is a user-defined data type

Classes



Data abstraction and encapsulation

Encapsulation : Combining a number of variables and functions into a single package

Abstraction : It refers to the act of representing essential features without including the details of implementation

Generally, data members are made private and are accessible to only class member functions

This insulation of data from direct access by the program is called data hiding or information hiding



Inheritance Inheritance is a process by which the

objects of one class inherit the properties of another class

Classes in C++ support the concept of hierarchical classification



Reusability The concept of inheritance providing

feature of reusability by additional features to the existing class without modifying the existing one leads to a new class



Polymorphism Polymorphism means the ability to take

more than one form Polymorphism is a mean by which we can

request an object to do something without knowing exactly what kind of object it is, and the object will figure out how to process the request appropriately



Binding refers to the linking of a procedure call to the code to be executed in response to the call

Dynamic binding means that the code associated with a given procedure call is not known until the time of call at runtime

This is associated with polymorphism and

inheritance

Dynamic binding



Message Passing An OOP consists of a set of objects that communicate

with each other

Message for an object is a request for execution of a procedure and therefore will invoke a function in the receiving object that generates the desired result

Message passing involves specifying the name of the object, the name of the function (message), and the information to be sent



List Abstract Data Type

A class template is a generic class declaration that allows the user to provide the data structure through parameters that the compiler resolved



Linked list ADT structure



Abstract representation of linked list

Linked list with header pointer



Standard Template Library

The C++ STL is a collection of Containers Iterators Algorithms



Standard Template Library

The STL is a part of the standard C++ class library and can be used as a standard approach for storing and processing data

The task of writing complex application codes can be made easy with the use of STL

The STL allows programmer to use these classes and functions directly in programs to increase

productivity



ContainersContainer class contains other objects. Container is a way to store data, whether the data consists of built-in types such as int and float, or of class objects

Container class Description Vector Array List Doubly linked list Slist Singly linked list Queue Queue structure, that is, FIFO structure Stack Stack structure, that is, LIFO structure Deque Combination of stack and queue, having facility for insertion and removal from both ends Set Set of unique elements Map Store key and data pair



Containers Categories

Containers are categorized into two types: Sequence containers Associative containers



The sequence containers are as follows: VectorsListsDeques

The containers that are derived from sequence containers are as follows:

StacksQueuesPriority queues

Sequence containers



List of functions for doubly ended queue



List of a few functions for list

in STL



List of containers and their characteristics



Associative Containers

An associative container is a collection of stored objects that allow fast retrieval using a key

In each container, the key must be unique There are four standard associative containers

classified into two classes: Sets (a) Set (b) Multiset Maps (a) Map (b) Multimap list



Algorithms The header <algorithm> defines a collection

of functions especially designed to be used on ranges of elements

These algorithms can be divided into six groups: Minimum and maximum algorithm Numeric algorithms Non-mutating sequence algorithms Sorting algorithm Set operations on sorted sequence Heap operations



Example Suppose we create an array of type int

storing marks of the student Then, int marks [6] = {73, 44, 42, 51, 59,

50}



We can use STL sort() assort(marks, marks + 6)

Here, marks is the start and marks + 6 is the end addresses, respectively

Other example of sorting vector is as follows: vector<int> m;/having values 73, 44, 42, 51, 59, 50

sort(m.begin(), m.end() );// Output is 42, 44, 50, 51, 59, 73

sort(v.begin(), v.end(), greater<int>()); // Output is 73, 59, 51, 50, 44, 42



replace() Replace value in range fill() Fill range with value remove() Remove value from range reverse() Reverse range sort() Sort elements in range partial_sort() Partially sort elements in range nth_element() Sort element in range binary_search() Test if value exists in sorted array merge() Merge sorted ranges min() Return the lesser of two arguments max() Return the greater of two arguments Min_element() Return the smallest element in range max_element() Return the largest element in range



IteratorsIterator—Iterator is pointer like entity, which is used to access individual data items in a container, and it is used to store and retrieve objects in C++STL defines five different iterators

Forward Bidirectional Random access Input iterator Output iterator



STL input iterator



STL Output Iterator



STL Forward Iterator



Bidirectional Iterator



Iterator Characteristics



Hierarchical relationship between

iterators



Iterator Operators



End of Chapter 1 5 …!

15. STL - Data Structures using C++ by Varsha Patil

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