Type of C Contants

C Contants are of following Types:-

Primary Constant :

• Integer
• Float
• Character

Secondary Constant :

• Array
• Pointer
• Structure
• Union
• Enum

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Rules of Constructing Integer and Float Constant:-

Sr.No	Rule	Integer	Float
1	Decimal Point	Not Allowed	Allowed
2	Sign	Positive or Negative	Positive or Negative
3	Default Sign	Positive	Positive
4	No of Digits	At least 1	At least 1
5	Min Value	-32768	-3.4e38
6	Max Value	+32767	3.4e38

Format of Real Number Constant :-

Syntax :                                 mantissa e exponent                   

Part	Type	Sign
Mantissa	Integer Part of Real Number	Has Optional +/- Sign
Exponent	Power of 10	Has Optional +/- Sign

Note :

• Exponent Part Should be Always Integer.
• Default Sign is Positive for both Mantissa as well as Exponent
• Special Characters not allowed
• Spaces are not allowed

Illustrative Examples :

Real Number	Representation
4567.45	4.56745e3
0.00045	4.5e-4

  

Consider Example 2 :

• Mantissa Should be in between 1 to 9
• Number : 0.00045 so shift decimal Point to Right by 4 Digit to obtain Mantissa as 4.5 
• Decimal Point is Shifted 4 times to Right 
• According to above Fig . Real Number : 4.5 e -4