The C Constants

In C constants are of two types.
1. Primary constant.
2. Secondary constant.








Rules for integer constant:

  • An integer constant must have at least one digit.
  • It must not have a decimal point.
  • It can 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 an integer constant.
  • The allowable range for integer constants is -32768 to 32767.



  • Must Read

    The range vary from compiler to compiler. Here the range is given for 16 bit compiler.



    Rules for real constant:

  • A real constant must have at least one digit.
  • It must have a decimal point.
  • It could be either positive or negative.
  • Default sign is positive.
  • No commas or blanks are allowed within a real constant.
  • The range of real constant is -3.4e38 to 3.4e38. (Where part before e is called mantissa   and part after e is called exponent)



  • Rules for character constant:

  • Character constant is a single alphabet, a single digit or a single special symbol enclosed within single inverted commas. Both the inverted commas should point to the left. For example, ’A’ is a valid character constant whereas ‘A’ is not.
  • The maximum length of a character constant can be 1 character.



  • Must Read

    The range vary from compiler to compiler. Here the range is given for 16 bit compiler.



    C Example

    #include<stdio.h>
    
    int main() {
    	int i=1;
    	float a=2.1;
    	char c='A';
    	printf("%d",i);
    	return 0;
    }
    

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