Introduction C++
C++ is an object oriented programming language. It was developed by Bjarne Stroustrup in 1979 at
Bell Laboratories in Murray Hill, New Jersey. He initially called the new language "C with Classes."
However, in 1983 the name was changed to C++. C++ is a superset of C. Stroustrup built C++ on the
foundation of C, including all of C’s features, attributes, and benefits. Most of the features that
Stroustrup added to C were designed to support object-oriented programming .These features
comprise of classes, inheritance, function overloading and operator overloading. C++ has many other
new features as well, including an improved approach to input/output (I/O) and a new way to write
comments.
C++ is used for developing applications such as editors, databases, personal file systems, networking
utilities, and communication programs. Because C++ shares C’s efficiency, much high-performance
systems software is constructed using C++.
A Simple C++ Program
#include<iostream.h>
#include<conio.h>
int main()
{
cout<< “Simple C++ program without using class”;
return 0;
}
Lines beginning with a hash sign (#) are directives read and interpreted by what is known as the pre-
processor. They are special lines interpreted before the compilation of the program itself begins. In
this case, the directive #include <iostream.h>, instructs the pre-processor to include a section of
standard C++ code, known as header iostream that allows to perform standard input and output
operations, such as writing the output of this program to the screen. The function named main is a
special function in all C++ programs; it is the function called when the program is run. The execution
of all C++ programs begins with the main function, regardless of where the function is actually
located within the code. The open brace ({) indicates the beginning of main's function definition, and
the closing brace (}) indicates its end. The statement: cout<< “Simple C++ program without using
class”; causes the string in quotation marks to be displayed on the screen. The identifier cout
(pronounced as c out) denotes an object. It points to the standard output device namely the console
monitor. The operator << is called insertion operator. It directs the string on its right to the object
on its left. The program ends with this statement: return 0; this causes zero to be returned to the
calling process (which is usually the operating system). Returning zero indicates that the program
terminated normally. Abnormal program termination should be signalled by returning a nonzero
value.
The general structure of C++ program with classes is shown as:
1. Documentation Section
2. Preprocessor Directives or Compiler Directives Section
(i) Link Section
(ii) Definition Section
3. Global Declaration Section
4. Class declaration or definition
5. Main C++ program function called main ( )
, C++ keywords
When a language is defined, one has to design a set of instructions to be used for communicating
with the computer to carry out specific operations. The set of instructions which are used in
programming, are called keywords. These are also known as reserved words of the language. They
have a specific meaning for the C++ compiler and should be used for giving specific instructions to
the computer. These words cannot be used for any other purpose, such as naming a variable. C++ is
a case-sensitive language, and it requires that all keywords be in lowercase. C++ keywords are:
auto break case char const continue default do
double else enum extern float for goto if
int long register return short signed sizeof static
struct switch typedef union unsigned void volatile while
Identifiers
An identifier is a name assigned to a function, variable, or any other user-defined item. Identifiers
can be from one to several characters long.
Rules for naming identifiers:
Variable names can start with any letter of the alphabet or an underscore. Next comes a
letter, a digit, or an underscore.
Uppercase and lowercase are distinct.
C++ keywords cannot be used as identifier.
Data types
Data type defines size and type of values that a variable can store along with the set of operations
that can be performed on that variable. C++ provides built-in data types that correspond to integers,
characters, floating-point values, and Boolean values. There are the seven basic data types in C++ as
shown below:
Type Meaning
char(character) holds 8-bit ASCII characters
wchar_t(Wide character) holds characters that are part of large character sets
int(Integer) represent integer numbers having no fractional part
float(floating point) stores real numbers in the range of about 3.4x10–
38to 3.4x10 38,with a
precision of seven digits.
double(Double floating point) Stores real numbers in the range from 1.7x10 –308
to1.7x10308 with a precision of 15 digits.
bool(Boolean) can have only two possible values: true and false.
Void Valueless
C++ is an object oriented programming language. It was developed by Bjarne Stroustrup in 1979 at
Bell Laboratories in Murray Hill, New Jersey. He initially called the new language "C with Classes."
However, in 1983 the name was changed to C++. C++ is a superset of C. Stroustrup built C++ on the
foundation of C, including all of C’s features, attributes, and benefits. Most of the features that
Stroustrup added to C were designed to support object-oriented programming .These features
comprise of classes, inheritance, function overloading and operator overloading. C++ has many other
new features as well, including an improved approach to input/output (I/O) and a new way to write
comments.
C++ is used for developing applications such as editors, databases, personal file systems, networking
utilities, and communication programs. Because C++ shares C’s efficiency, much high-performance
systems software is constructed using C++.
A Simple C++ Program
#include<iostream.h>
#include<conio.h>
int main()
{
cout<< “Simple C++ program without using class”;
return 0;
}
Lines beginning with a hash sign (#) are directives read and interpreted by what is known as the pre-
processor. They are special lines interpreted before the compilation of the program itself begins. In
this case, the directive #include <iostream.h>, instructs the pre-processor to include a section of
standard C++ code, known as header iostream that allows to perform standard input and output
operations, such as writing the output of this program to the screen. The function named main is a
special function in all C++ programs; it is the function called when the program is run. The execution
of all C++ programs begins with the main function, regardless of where the function is actually
located within the code. The open brace ({) indicates the beginning of main's function definition, and
the closing brace (}) indicates its end. The statement: cout<< “Simple C++ program without using
class”; causes the string in quotation marks to be displayed on the screen. The identifier cout
(pronounced as c out) denotes an object. It points to the standard output device namely the console
monitor. The operator << is called insertion operator. It directs the string on its right to the object
on its left. The program ends with this statement: return 0; this causes zero to be returned to the
calling process (which is usually the operating system). Returning zero indicates that the program
terminated normally. Abnormal program termination should be signalled by returning a nonzero
value.
The general structure of C++ program with classes is shown as:
1. Documentation Section
2. Preprocessor Directives or Compiler Directives Section
(i) Link Section
(ii) Definition Section
3. Global Declaration Section
4. Class declaration or definition
5. Main C++ program function called main ( )
, C++ keywords
When a language is defined, one has to design a set of instructions to be used for communicating
with the computer to carry out specific operations. The set of instructions which are used in
programming, are called keywords. These are also known as reserved words of the language. They
have a specific meaning for the C++ compiler and should be used for giving specific instructions to
the computer. These words cannot be used for any other purpose, such as naming a variable. C++ is
a case-sensitive language, and it requires that all keywords be in lowercase. C++ keywords are:
auto break case char const continue default do
double else enum extern float for goto if
int long register return short signed sizeof static
struct switch typedef union unsigned void volatile while
Identifiers
An identifier is a name assigned to a function, variable, or any other user-defined item. Identifiers
can be from one to several characters long.
Rules for naming identifiers:
Variable names can start with any letter of the alphabet or an underscore. Next comes a
letter, a digit, or an underscore.
Uppercase and lowercase are distinct.
C++ keywords cannot be used as identifier.
Data types
Data type defines size and type of values that a variable can store along with the set of operations
that can be performed on that variable. C++ provides built-in data types that correspond to integers,
characters, floating-point values, and Boolean values. There are the seven basic data types in C++ as
shown below:
Type Meaning
char(character) holds 8-bit ASCII characters
wchar_t(Wide character) holds characters that are part of large character sets
int(Integer) represent integer numbers having no fractional part
float(floating point) stores real numbers in the range of about 3.4x10–
38to 3.4x10 38,with a
precision of seven digits.
double(Double floating point) Stores real numbers in the range from 1.7x10 –308
to1.7x10308 with a precision of 15 digits.
bool(Boolean) can have only two possible values: true and false.
Void Valueless
