Constants

Constants

• C Constants are also like normal variables. But, only difference is, their values can not be modified by the program once they are defined.
• Constants refer to fixed values. They are also called as literals
• Constants may be belonging to any of the data type.

Types of C constant:

1.     Integer constants
2.     Real or Floating point constants
3.     Octal & Hexadecimal constants
4.     Character constants
5.     String constants
6.     Backslash character constants

Rules for constructing C constant:

1. Integer Constants in C:

• An integer constant must have at least one digit.
• It must not have a decimal point.
• It can either be positive or negative.
• No commas or blanks are allowed within an integer constant.
• If no sign precedes an integer constant, it is assumed to be positive.
• The allowable range for integer constants is -32768 to 32767.

2. Real constants in C:

• A real constant must have at least one digit
• It must have a decimal point
• It could be either positive or negative
• If no sign precedes an integer constant, it is assumed to be positive.
• No commas or blanks are allowed within a real constant.

3. Character and string constants in C:

• A character constant is a single alphabet, a single digit or a single special symbol enclosed within single quotes.
• The maximum length of a character constant is 1 character.
• String constants are  enclosed within double quotes.

4. Backslash Character Constants in C:

• There are some characters which have special meaning in C language.
• They should be preceded by backslash symbol to make use of special function of them.
• Given below is the list of special characters and their purpose.