Variables and Constants

In the previous chapter we have learnt about basic concept of Tokens, Keywords, Identifier, compilation and execution process of c etc. In this chapter we are going to learn about the Variables and Constants in C Programming.

Variables and Constants in C programming:


As the name suggest, Variable is a memory location that can be used to store data whose values can be altered in program based on certain condition.

Data_type identifier_name;

Variable Example:

In the above program v1, v2, sum are the variables which holds the value which can be changed.


Constants are the data values which cannot be altered or modified throughout the program whose value is fixed for the entire programs. Constants are of following type:

    1. Integer constant
    2. Character constant

variables and constants

  1. String constant
  2. Floating constant

Integer constant:
There are of three types of integer constant

  1. Decimal constants-0,1,2,3,4,5,6,7,8,9(base 10).
  2. Octal constants-0,1,2,3,4,5,6,7 (base 8).
  3. Hexadecimal constants- 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F(base 16).

Character constant:
These are generally written under single quote.
For example: ‘A’,’B’,’>’ etc.

String constant:
These constants are written under double quotes.
For example:”[email protected]

Floating constants:
These are constants used to represent floating point values. Floating constants have these type: float, double or long double, exponential
For example:
9.5f –float constant
9.5- double constant
9.5l- long double constant
3.5e0- exponential form double constant

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