Programming Language

Programming Language
A programming language is said to use
static typing when type checking is
performed during compile-time as
opposed to run-time.

OOP
Object-Oriented Programming
• C++ fully supports object-oriented
programming, including the four pillars of
object-oriented development:
• Encapsulation
• Data hiding
• Inheritance
• Polymorphism

Encapsulation
• Encapsulation is an Object
Oriented Programming concept that binds
together the data and functions that
manipulate the data, and that keeps both safe
from outside interference and misuse.
Dataencapsulation led to the
important OOP concept of data hiding.

Data hiding
• Data hiding, also known as
information hiding or data encapsulation in
computer science, is a software development
technique used inobject-
oriented programming. It is mainly used
to hide internal object details, i.e. the design
decisions in a computer program that are
most likely to change.

inheritance
• In object-
oriented programming, inheritance enables
new objects to take on the properties of
existing objects. A class that is used as the
basis for inheritance is called a superclass or
base class. A class thatinherits from a
superclass is called a subclass or derived class.

Polymorphism
• Polymorphism refers to a programming
language'sability to process objects differently
depending on their data type orclass.

How (OOP) languages are designed to
overcome these problems.
• The basic unit of OOP is a class, which encapsulates
both the static attributes and dynamic behaviorswithin
a "box", and specifies the public interface for using
these boxes
• OOP languages permit higher level of abstraction for
solving real-life problems. The traditional procedural
language (such as C and Pascal) forces you to think in
terms of the structure of the computer (e.g. memory
bits and bytes, array, decision, loop) rather than
thinking in terms of the problem you are trying to
solve.

Benefits of OOP
• Ease in software design as you could think in
the problem space rather than the machine's
bits and bytes. You are dealing with high-level
concepts and abstractions
• Ease in software maintenance: object-
oriented software are easier to understand,
therefore easier to test, debug, and maintain.

• A class can be visualized as a three-compartment box, as
illustrated:
• Classname (or identifier): identifies the class.
• Data Members or Variables (or attributes, states, fields):
contains the static attributes of the class.
• Member Functions (or methods, behaviors, operations):
contains the dynamic operations of the class.
• In other words, a class encapsulates the static attributes
(data) and dynamic behaviors (operations that operate on
the data) in a box.
• Class Members: The data members and member
functions are collectively called class members.

Standard Libraries
Standard C++ consists of three important parts:
• The core language giving all the building
blocks including variables, data types and
literals, etc.
• The C++ Standard Library giving a rich set of
functions manipulating files, strings, etc.
• The Standard Template Library (STL) giving a
rich set of methods manipulating data
structures, etc.

ANSI Standard
• The ANSI standard is an attempt to ensure
that C++ is portable -- that code you write for
Microsoft's compiler will compile without
errors, using a compiler on a Mac, UNIX, a
Windows box, or an Alpha.
• The ANSI standard has been stable for a while,
and all the major C++ compiler manufacturers
support the ANSI standard.

Text Editor:
• This will be used to type your program. Examples
of few editors include Windows Notepad, OS Edit
command, Brief, Epsilon, EMACS, and vim or vi.
• Name and version of text editor can vary on
different operating systems. For example,
Notepad will be used on Windows and vim or vi
can be used on windows as well as Linux, or
UNIX.
• The files you create with your editor are called
source files and for C++ they typically are named
with the extension .cpp, .cp, or .c.

Translator
• Compiler
• Interpreter

Behavior of the Language
• Object - Objects have states and behaviors. Example: A dog
has states - color, name, breed as well as behaviors -
wagging, barking, eating. An object is an instance of a class.
• Class - A class can be defined as a template/blueprint that
describes the behaviors/states that object of its type
support.
• Methods - A method is basically a behavior. A class can
contain many methods. It is in methods where the logics
are written, data is manipulated and all the actions are
executed.
• Instant Variables - Each object has its unique set of instant
variables. An object's state is created by the values
assigned to these instant variables.

C++ Program Structure
#include <iostream>
using namespace std;
// main() is where program execution begins.
int main()
{
cout << "Hello World";
// prints Hello World
return 0;
}

Expalination
• The C++ language defines several headers, which contain
information that is either necessary or useful to your program. For
this program, the header <iostream> is needed.
• The line using namespace std; tells the compiler to use the std
namespace. Namespaces are a relatively recent addition to C++.
• The next line // main() is where program execution begins. is a
single-line comment available in C++. Single-line comments begin
with // and stop at the end of the line.
• The line int main() is the main function where program execution
begins.
• The next line cout << "This is my first C++ program.";causes the
message "This is my first C++ program" to be displayed on the
screen.
• The next line return 0; terminates main( )function and causes it to
return the value 0 to the calling process.

C++ Data Types
• While doing programming in any programming
language, you need to use various variables to
store various information. Variables are nothing
but reserved memory locations to store values.
This means that when you create a variable you
reserve some space in memory.
• You may like to store information of various data
types like character, wide character, integer,
floating point, double floating point, boolean .

seven basic C++ data types
Type Keyword
• Boolean bool
• Character char
• Integer int
• Floating point float
• Double floating point double
• Valueless void
• Wide character wchar_t

Loop
• Programming languages provide various
control structures that allow for more
complicated execution paths.
• A loop statement allows us to execute a
statement or group of statements multiple
times and following is the general from of a
loop statement in most of the programming
languages:

Types of Loop
• Loop Types Description
• while loop
Repeats a statement or group of statements while a given condition
is true. It tests the condition before executing the loop body.
• for loop
Execute a sequence of statements multiple times and abbreviates
the code that manages the loop variable.
• do...while loop
Like a while statement, except that it tests the condition at the end
of the loop body
• nested loops
You can use one or more loop inside any another while, for or
do..while loop.

Loop Control Statements:
• Loop control statements change execution
from its normal sequence. When execution
leaves a scope, all automatic objects that were
created in that scope are destroyed.

control statements
• break statement
• Terminates the loop or switch statement and transfers
execution to the statement immediately following the
loop or switch.
• continue statement
• Causes the loop to skip the remainder of its body and
immediately retest its condition prior to reiterating.
• goto statement
• Transfers control to the labeled statement. Though it is
not advised to use goto statement in your program.

For Loop
• The “for loop” loops from one number to
another number and increases by a specified
value each time.
The “for loop” uses the following structure:
for (Start value; end condition; increase value)
statement(s);

Example
#include<iostream>
int main()
{
int i;
for (i = 0; i < 10; i++)
{
cout << “My Name" << "n";
cout << “Pakistan" << "n";
}
return 0;
}

While loop
• The while loop can be used if you don’t know
how many times a loop must run.

Examples
#include<iostream>
int main()
{
int counter, howmuch;
cin >> howmuch;
counter = 0;
while ( counter < howmuch)
{
counter++;
cout << counter << 'n';
}
return 0;
}

do while loop
The “do while loop” is almost the same as the
while loop. The “do while loop” has the
following form:

Example
#include <iostream>
int main()
{
int counter, howmuch;
cin >> howmuch;
counter = 0;
do
{
counter++;
cout << counter << 'n';
}
while ( counter < howmuch);
return 0;
}

Break and continue
• To exit a loop you can use the break statement
at any time. This can be very useful if you
want to stop running a loop because a
condition has been met other than the loop
end condition

Example
#include <iostream>
int main()
{
int i;
i = 0;
while ( i < 20 )
{ i++;
cout << "Hellon";
if ( i == 10)
break;
}
return 0;
}

Example
#include <iostream>
int main()
{
int i;
i = 0;
while ( i < 20 )
{
i++;
continue;
cout << "Hellon";
if ( i == 10)
break;
}
return 0;
}

Programming Language

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