This document presents an overview of constructing C++ programs, focusing on the fundamental building blocks called tokens. It categorizes these tokens into keywords, identifiers, constants, strings, operators, and punctuators while providing definitions and examples for each category. Additionally, it emphasizes naming conventions for identifiers and the importance of valid syntax in C++ programming.

1. NAME : R.DEVIPRIYA
REG. NO : 1021719BD020
DEPARTMENT: COMPUTER
SCIENCE
CLASS : XI

2. TOPIC
?

3. How do we
construct C++
program?

4. TOPIC
TOKENS IN C++

5. TOKENS
 Tokens are the basic building blocks in C++
language. The smallest individual units in a
program are known as Tokens.
 A program is constructed using a combination of
these tokens

6.  C++ has following tokens
TOKENS
Keywords Identifiers Constants String Operators Punctuators

7. EXAMPLES:
int, float, double,
switch, break,
char, const,
continue, default,
for, if, static, void,
sizeof, while,
return, long, do
etc.,
KEYWORDS
Definition:
Sequence of characters that have fixed meaning.
 Keywords must be written in lower case
 Reserved identifiers and can’t be used as
names for the
1) Program variables
2) user defined program elements

8. IDENTIFIERS
 It is the name given to a variable, function,
array etc. These are the user defined names
and consist of the sequence of the letters and
digits with a letter as a first character.
Variables in C++
Numeric
Variables
To store either
integer values or
floating point values
Character
Variables
Albhabets and numbers
from 0-9 inserted
between single quotes

9. EXAMPLES:
Valid Identifiers
Result
Test2
_sum
Power
Invalid Identifiers
Su-
// containing special
character '-'.
2data // the first le
tter is a digit.
break // use of a
keyword.
NAMING CONVENTION
 Only alphabetic characters, digits, and
underscores are allowed.
 The identifier name cannot start with a
digit or a number
 C++ identifiers are case-sensitive.
 A declared keyword cannot be used
as a variable name.

10. Is this a VALID IDENTIFIER?
Num&add

11. Num&add is A INVALID
IDENTIFIER
REASON: special character
except underescore is not
permitted

12. CONSTANTS
Definition: The Quantities whose value do not
change during the program execution are
known CONSTANTS

13. STRINGS
 Definition:
A group of characters that are treated as a single item data
enclosed in double quotes are known as STRINGS
 General Syntax :
 char string-name[size];
 Size determines the number of characters in the string name
Example : char country[9]= “ INDIA”;

14. Is this a VALID STRING?
‘ WELCOME ’

15. ‘ WELCOME ’ is INVALID
STRING
REASON: Valid String should
be enclosed within double
quotes

16. PUNCTUATORS
 DEFINITION:
Punctuators are symbols, which are used as
delimiters, while constructing a C++ program. They
are also called as “Separators”.

17. OPERATORS
 DEFINITION:
An operator is a symbol that tells the compiler to
perform specific mathematical or logical manipulations.
C++ is rich in built-in operators

18. THANK YOU