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.
int v1, v2, sum;
v1 = 100, v2 = 200;
sum = v1 + v2;
printf (“Sum of V1 and v2 is = %d \n”, sum);
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:
- Integer constant
- Character constant
- String constant
- Floating constant
There are of three types of integer constant
- Decimal constants-0,1,2,3,4,5,6,7,8,9(base 10).
- Octal constants-0,1,2,3,4,5,6,7 (base 8).
- Hexadecimal constants- 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F(base 16).
These are generally written under single quote.
For example: ‘A’,’B’,’>’ etc.
These constants are written under double quotes.
For example:”[email protected]”
These are constants used to represent floating point values. Floating constants have these type: float, double or long double, exponential
9.5f –float constant
9.5- double constant
9.5l- long double constant
3.5e0- exponential form double constant