Getting Started with C++

WEL COME
PRAVEEN M JIGAJINNI
PGT (Computer Science)
MCA, MSc[IT], MTech[IT],MPhil (Comp.Sci), PGDCA, ADCA,
Dc. Sc. & Engg.

Reference Book
CLASS XI
By
Sumita Arora

GETTING
STARTED
WITH
C++
CHAPTER 6

INTRODUCTION
C ++ Programming language was
developed at AT & T Bells LAB early in
1980’s by BJARNE STROUSTRUP.
 STROUSTRUP added some features
to his favorite language Simula 67.
(Earliest OOP).
STROUSTRUP called “ C with Classes
”.
C++ ( C Plus Plus) is named by Rick
Masitti.

Born
December 30, 1950 ) (age 60)
Aarhus, Denmark
Occupation
College of Engineering Chair in
Computer Science Professor, Texas
A&M University USA
Known for The creation of C++
BJARNE
STROUSTRUP

BJARNE STROUSTRUP
Bjarne Stroustrup giving a talk at Kent
State University on C++0x in 2007.

C++ CHARACTER SET
Letters:- A-Z, a-z
Digits:- 0 to 9
Special Symbols:- space + - / ( ) [ ] = !
= < > , ‘ “ $ # ; : ? &
White Spaces:- Blank Space , Horizontal
Tab, Vertical tab, Carriage Return.
Other Characters:- C++ can process any
of the 256 ASCII Characters as data or as
literal.

TOKENS
The Smallest individual unit in a program
is known as Token.
Lexical Unit is the another name given to
Token.
C++ has following Tokens
1) Key words 2) Identifiers 3) Literals
4) Punctuators 5) Operators

KEY WORDS
Key words are the words that convey
special meaning to the compiler.
Key words are also called as Reserved
words meaning their meaning is reserved
in C++.
Some of Key words are,
float int auto extern double
case do while goto…etc

IDENTIFIERS
Identifier is an arbitrary long sequence of
letters and digits.
The first character must be letter.
The underscore ( _ ) counts as letter.
Upper and Lower case letters are
different.
All characters are significant.

EXAMPLES OF
IDENTIFIERS
C++ is a Case Sensitive Language as it
treats upper case letters and lower case
letters differently.
Some Valid identifiers,
Myfile DATE9_7_8 z3t9x3
 MYFILE _DS _FXR
Some Invalid identifiers,
DATA-REC 28dre break

LITERALS
Literals often referred to as constants
These are the data items that never
change their value during the program
run.

TYPES OF C++
LITERALS
INTEGER – CONSTANT
CHARACTER – CONSTANT
FLOATING – CONSTANT
 STRING – LITERAL

INTEGER CONSTANT
These are the whole numbers without any
fractional part.
An integer constant must have at least
one digit and must not contain fractional
part.
It may contain + or - Sign.
A number with no sign is assumed as
positive.
Commas can not appear in integer
constant.

TYPES OF INTEGER
CONSTANTS
DECIMAL INTEGER CONSTANTS
OCTAL INTEGER CONSTANTS
HEXADECIMAL CONSTANTS

DECIMAL INTEGER
CONSTANT
An integer constant consisting of
sequence of digits is taken to be decimal
integer constant unless it begins with 0.
For instance 1234,56,+86,-56,-89,-22 are
decimal integer constant.

OCTAL INTEGER CONSANT
A sequence of digits starting with 0(digit
Zero) is taken to be an octal integer
constant.
 for instance Decimal 8 is written as 010
as octal integer
8 10 =10 8
Decimal 12 is written as
12 10 = 14 8

HEXADECIMAL INTEGER
CONSTANT
A Sequence of Digits preceded by 0x or
0X is taken to be an hexadecimal integer
constant.
For instance decimal 12 is written as
 1210 = 0XC
The Suffix l or L and u or U is attached to
any constant indicates as long and
unsigned respectively
For Example:- 12L,189U …etc

CHARACTER CONSTANT
A character constant is one character
enclosed within single quotes
Valid constants ‘a’ ‘z’ ‘k’
Invalid Constants a z k
In c++ character constant must have
single character and must be enclosed in
single quotes.

NONGRAPHIC CHARACTERS
Nongraphic character constants are those
characters that can not be typed directly
from the keyboard.
e.g backspace, tab, carriage return
C++ Allows programmers to have certain
nongraphic characters.

ESCAPE SEQUENCES
Escape sequences are nongraphic
character constants these are also called
as non printing characters.
These nongraphic characters are
represented by means of escape
sequence and is represented by a
backslash ( ) followed by a one or more
character.

ESCAPE SEQUCENCE IN C++
Escape Sequence Non Graphic Character
 a Bell
 b Back Space
 f Form Feed
 n New Line
 r Carriage Return
 t Horizontal Tab
 v Vertical Tab
 ’ Single Quote
 ” Double Quote
 ? Question Mark
 on Octal Number ( On represents
the number in octal)
 xHn Hexadecimal number
 0 Null

NOTE
THESE ESCAPE SQUENCES ARE USED IN
OUT PUT STATEMENT COUT
FOR EX:
cout<<“nt Wel Come”; // Right statement
cin>>”nt”>>n; - Wrong statement
Do not use in cin statements

FLOATING CONSTANTS
Floating constants are also called as Real
constants. These may be written in one of two of
forms called fractional form or exponent form.
A real constant in fractional form must have one
digit before a decimal point and at least one digit
after the decimal point. It may also have either
+ve or –ve sign preceding it. A real constant
with no sign is assumed to be positive.

EXAMPLES OF REAL CONSTANTS
The following are the valid real constants
in fractional form.
2.0 17.5 -89.9 -0.000732
The following are the invalid real constants
in fractional
7 7. +27/3 24.34.32
12,45,344.09

REAL CONSTANTS IN EXPONENT FORM
A Real constant in exponent form has two
parts
1. Mantissa
2. Exponent
Mantissa must be either an integer or
proper real constant. The mantissa is
followed by letter E or e and the exponent
must be an integer.

EXAMPLE OF REAL CONSTANTS
The floating point number 5.8 can be written as,
0.58 x 101
=0.58E01 or 0.58e01, here E01 or
e01 represents 101
0.58 E01
Mantissa part Exponent part
Valid Real Constants : 123E03, 0.76e02, -0.12e-2
Invalid Real Constants: 172.E03, 1.2E,0.4E2.3

STRING LITERAL
A String Literal is a sequence of
characters surrounded by double quotes
 A Multi character constants are treated as
string literals.
For Example: “abc” in the memory this
string is represented as “abc0” i.e along
with the terminating character (Slash
Zero).
String is an array of character.

PUNCTUATORS
Punctuators are also called as separators The
Followings are used as punctuators
Brackets [ ]
Parantheses ( )
Braces { }
Comma ,
Semicolon ;
Colon :
Asterisk *
Ellipsis …
Equal Sign =
Pound Sign #

OPERATORS
Operators are tokens that triggers some
computation when applied to a variable
and other objects in an function.
Unary Operators are those operators they
act upon one operand.
OR
operators that require one operator to
operate upon.

UNARY OPERATORS
& Address Operator
* Indirection Operator
+ Unary Plus
- Unary Minus
~ Bitwise Compliment
++ Increment Operator
-- Decrement Operator
! Logical Negation

BINARY OPERATORS
Binary Operators are those operators that
require two operands to operate upon.
Arithmetic Operators
+ Addition
- Subtraction
* Multiplication
/ Division
% Remainder or Modulus

SHIFT OPERATORS
<< (Shift Left)
>> (Shift Right)
For More information you will study in
future chapters.

LOGICAL OPERATORS
&& Logical AND
|| Logical OR

ASSIGNMENT OPERATORS
= Assignment Operator
*= Assign Product
/= Assign Quotient
%= Assign Remainder
+= Assign Sum
-= Assign Minus
<<= Assign Left Shift
>>= Assign Right Shift
&= Assign Bitwise AND
^= Assign Bitwise XOR
|= Assign Bitwise OR

Relational Operator
< Less than
> Greater than
<= Less than equal to
>= Greater than equal to
== Equal to
!= Not equal to

COMPONENT SELECTION OPERATORS
Direct component selector
Indirect component selector

CLASS MEMBER OPERATORS
:: Scope access or scope resolution
.* Difference pointer to class member
* Difference pointer to class member

CONDITIONAL OPERATOR
? :
Further Details you will study in
FLOW CONTROL CHAPTER

ORDER OF PRECEDENCE
( ) [ ]
! ~ + - ++ -- & *
* / %
+ -
<< >>
< <= >>=
== !=
&
^
|
&&
?:
= *= /= %= + = - = &= ^= | = < < = > >=

A FIRST LOOK AT CPP PROGRAM
// My First Program
# include <iostream.h>
int main ()
{
cout<<“Wel Come To C++ Programming”;
return 0;
}
The program produces the output as,
Wel Come To C++ Programming

FIRST PROGRAM
// My First C++ Program
This is the comment. All lines beginning with
// are the comments in the program.
The comments are the non executable
statements. When ever compiler identifies
this is comment then it ignores
// is the single line comment
Starting with /* and ended with */ is used for
multi line comments

FIRST PROGRAM
# include <iostream.h>
Statement begin with # (hash or pound) sign
are the directives for the preprocessor,
that means these statement are
processed before compilation takes place.
The # include <iostream.h> statement tells
compiler’s preprocessor to include the
header file iostream.h in the program

FIRST PROGRAM
int main()
This line indicates the beginning of the
main function. The main() function is the
point where C++ program begin their
execution.
return 0;
The return statement makes the main() to
finish and it returns a value.

NOTE
• Every Executable statement in the C++
must be terminated by a semi colon
;

Why iostream.h ?
• The header file iostream.h is included in
every C++ program to implement the
input/output facilities.
Input /output facilities are not defined in
the C++ language rather they are
implemented through a component of C++
standard library.

THE FUNTION OF I/O LIBRARY – iostream.h
1. At the lowest level, where the notion of data
type is missing and the files are treated as
streams of bytes, the I/O library manages the
transfer of these bytes.
2. At the user level where the notion of data type
is present, I/O library manages the interface
between these two levels i.e between user
level and the implementation level

PREDEFINED STREAMS IN I/O LIBRARY
At the lowest level files are implemented
as streams of bytes, then
What is STREAM?
A Stream is simply a sequence of bytes.
Input and output operations are
supported by the istream (input stream)
and ostream (output stream) classes.

PREDEFINED STREAMS IN I/O LIBRARY
The ostream output operation, referred to
as insertion and is performed by insertion
operator <<
The istream input operation, referred to as
extraction and is performed by extraction
operator >>

EXTRACTION AND INSERTION SYMBOLS
extraction operator Symbol is,
>>insertion operator symbol is,
<<

cin and cout statements
cin (pronounced as see-in) stands for
console input.
cout (pronounced as see-out) stands for
console output.

SYNTAX OF cin STATEMENT
The general format or the syntax of cin statement is,
cin>>variablename;
Or
cin>>variablename1>>variablename2>>variable
name3………>>variablenamen;
for example if four variables are to be input form the
keyboard then,
cin>>a>>b>>c>>d;
Or the same statement can be written as follows,
cin>>a;
cin>>b;
cin>>c;
cin>>d;

SYNTAX OF cout STATEMENT
• The general format or the syntax of cout statement is,
cout<<variablename;
Or
cout<<variablename1<<variablename2<<variable name3………
<<variablenamen;
for example if four variables are to be input form the keyboard
then,
cout<<a <<b <<c <<d;
Or the same statement can be written as follows,
cout<<a;
cout<<b;
cout<<c;
cout<<d;

cout STATEMENT
Another way of writing cout statement is,
cout<<string<<variablename;
where,
String is a sequence of characters enclosed
within a double quotation.
Variable name is the value of variable which
is to be printed after the message(string)

cout STATEMENT
totalamt;=6700;
cout<<“The Total Amount is = “<<totalamt;
Here, in this example
The Total Amount is= is the string
And the totalamt is the variable name, the
value of the total is printed
Out put of this statement is as follows
The total Amount is = 6700

cout STATEMENT
As studied escape sequences are used in out
put (cout) statements
• cout<<“ntBasic Pay=“<<basic<<“nt
DA=“<<da<<“nt HRA = “<<hra<<“nt Gross
Salary = “<<gs;
output of the above statement is,
Basic Pay=5900
DA=40
HRA =30
Gross Salary = 10030

COMMENTS
The comments are the non executable
statements. When ever compiler identifies
this is comment then it ignores. There are
two types of comments in C++
Single Line Comment (//)
Multi Line Comment (starts with /* and
ends with */

COMMENTS
The comments are the non executable statements.
When ever compiler identifies this is comment
then it ignores. Single Lien Comment Example
// My First C++ Program
This is the comment. All lines beginning with // are
the comments in the program.
Starting with /* and ended with */ is used for multi
line comments
Multi Line Comment Example
/* Write a CPP Program that calculates the sum
and average of three numbers*/

I/O OPERATORS
Input coming from the user’s terminal
referred to as standard input is tied to the
predefined iostream cin and output
directed to the user’s terminal, referred to
as standard output, is tied to the
predefined iostream cout.

OUTPUT OPERATOR “<<’’
The output operator (“<<’’) (“put to’’), also
called as stream insertion operator is used
to direct a value to the standard output
device.
For example
cout<<“The Sum of 5 + 2 = “;
cout<< 5 + 2 ;
The statement will produce following output
The Sum of 5 + 2 = 7

OUTPUT OPERATOR <<
Now observe the output of following statement.
cout<< “The Sum of 5 + 2 is “;
cout<< 5 + 2;
cout<<“n”;
cout<<“The Result pf 8 – 2 is“;
cout<<8 – 2 ;
The Output of abve set of statements will be as
follows,
The Sum of 5 + 2 is 7
The Result pf 8 – 2 is 6

OUTPUT OPERATOR <<
The same statements can be written by using
single cout statement
cout<< “The Sum of 5 + 2 is
<< 5 + 2<<“n”
<<“The Result pf 8 – 2 is“<<8 – 2 ;
The Output will be same but code is reduced.
The Sum of 5 + 2 is 7
The Result pf 8 – 2 is 6
Note: Stream insertion operator >> signifies that
the insert the value that follows in to the stream
named cout.

/* Write a C ++ Program that
prints the sum of two values */
#include <iostream.h> // for I/O Operation
#include<conio.h>// for clrscr() and getch() functions.
Int main()
{ cirscr() ;
int value1, value2, sum ;
cout << “Enter First Value:”;
cin>>value1;
cout<<“Enter Second Value:”;
cin>>value2;

Program contd..
sum=value1+value2;
cout<<“The Sum of two given values is : “;
cout<<sum;
return 0;
}
Definition: Variable refers to a storage area whose
contents can vary during processing. In this
example sum , value1 , valu2 are the variables.
NOTE: The Stream extraction operator >>, signifies “extract the next
value” from the stream named cin and assign it to the next named
variable

OUTPUT OF PROGRAM
The output produced by the program is as
follows,
Enter the First value: 6
Enter the Second value : 7
The Sum of the given value is : 13

CASCADING I/O OPERATOR
• The Multiple use of input or output operators
(“>>” or “>>”) in one statement is called
cascading of I/O operators.
• For Example OUTPUT OPERATOR
cout<<“The sum of “;
cout<<value1;
cout<< “and “;
cout<<value2;
cout<<“ is “;
cout<<value1+value2;
This can be using cascading of output operator as,
cout<<“The sum of “<<value1<< “and “<<value2<<“ is “
<<value1+value2;

CASCADING I/O OPERATOR
• For Example INPUT OPERATOR
cout<<“Enter the two values “;
cin>>value1;
cin>>value2;
This can be using cascading of input operator as,
cout<<“Enter the two values “;
cin>>value1>>value2;

INVOKING TURBO C++
• To invoke ( load ) Turobo C++ Editor, Click on
start and type cmd and press enter key. Go to
root directory c and then type the following
commands.
C:>cd tc
C:tc>cd bin
C:tcbin>tc
After typing these commands at dos prompt
you will see an C++ editor on the screen.

C++ EDITOR
Use F5 to Maximize Window and F6 to navigate between opened files

COMPILING PROGRAM ALT + C or press ALT + F9

RUNING PROGRAM ALT + R or CTRL + F9

ROLE OF COMPILER
• A part of the compiler’s job is to analyze the
program code for “Correctness” if the
meaning of the program is correct then
compiler will not detect errors.
Types of Errors are,
1. Syntax Errors
2. Semantic Errors
3. Type of Errors
4. Run Time Errors.
5. Logical Errors

SYNTAX ERROR
Syntax errors refer to formal rules
governing the construction of valid
statements in a language.
Syntax errors occur when rules of a
programming language are misused i.e.,
when a grammatical rule of C++ is
violated.

1. SYNTAX ERROR
• For instance in the following program segment,
main()
{
int a,b:
cin>>a>>b;
cout<<a+b,
return 0;
}

2. SEMANTICS ERROR
• Semantics error occur when statements
are not meaningful
Semantics refers to the set of rules which
give the meaning of the statement.
For example,
Sita plays Guitar
This statement is syntactically and
semantically correct and it has some
meaning.

2. SEMANTICS ERROR
See the following statement,
Guitar plays sita
is syntactically correct (syntax is correct) but
semantically incorrect. Similarly, there are
semantics rules of programming language,
violation of which results in semantical errors.
X * Y = Z
will result in semantical error as an expression
can not come on the left side of an assignment
statement.

3. TYPE ERRORS
Data in C++ has an associated data type.
The value 7, for instance, is an integer and
‘a’ is a character constant “Hi” is a string. If
a function is given wrong type of data,
then Type Error is assigned by compiler
For Example :
char a[]=“Hi”;
pow(a,2);
This will result in type error.

4. RUNTIME ERRORS
A Run time error is that occurs during execution
of the program. It is caused because of some
illegal operation taking place.
For example
1. If a program is trying to open a file which does
not exists or it could not be opened(meaning file
is corrupted), results into an execution error.
2. An expression is trying to divide a number by
zero are RUN TIME ERRORS.

5. LOGICAL ERRORS
• A Logical Error is that error which is causes a
program to produce incorrect or undesired
output.
for instance,
ctr=1;
while(ctr>10)
{
cout<<n *ctr;
ctr=ctr+1;
}

MORE ABOUT COMPILER
• A Compiler reports an error by flashing an error
message. An Error message contains a line
number and a brief description of the error.
A second thing, a compiler does is, it translates
the corrected program text into object or
assembly instruction text understood by the
compiler, this process of translation is called
code generation. After code generation actual
program execution takes place.

Getting Started with C++

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