Using Constants in C
Constants in C
- Like a variable, a constant is a data storage location used by your program.
- Unlike a variable, the value stored in a constant can’t be changed during program execution.
- It is a fix value which can not be change during the program execution.
- There are four types of constant
1. Integer Constant
- It contains only Digits 0 to 9
- Eg. 23
2. Floating Pont Constant
- It contains only Digits 0 to 9 and Decimal point
- Eg. 20.12
3. Character Constant
- It contains only Single Character
- Eg. ‘A’
4. String Constant
- It contains Sequence of one or more Characters terminated by a NULL Characters
- Eg. “Hello India”
There are two method s to Define a Constant
1. Using const Keyword
2. Using #define directive
 Using const Keyword
|const int count = 100;|
const float pi = 3.14159;
- You can declare the const before or after the type. Choose one an stick to it.
- It is usual to initialise a const with a value as it cannot get a value any other way.
 Using #define directive
#define PI 3.14159