There are two types of constant normally literal constants and symbolic constants, which are classified, based on their representation.
1) Literal constants as a represented by their value. E.g: numbers like 1,2.3 or the characters like “z”, “y” are all Literal constants .
The classification of constants given bellow.
a) C++ Integer:
Integers are numbers without fractional parts. Integers can be decimal, Octal or hexadecimal numbers. E.g.21 (decimal) ,023(Octal), 0*15(hexadecimal).
They can also be long are unsigned. To denote long, unsigned, suffixes such as P,Q,I can be used. E.g.155U, 1145u, 1L, 9LU, 91l (91 and L)
b) C++ Floating literal :
Floating literal character the numbers with fractional parts. There are written in specific or common notation. Using, the specific notation, the exponent can be written as high that E or e fifth (E or e represents the power of 10) fifth. By default the Floating literal task than double precision (12 digit after decimal points).
Following the value with either F or f indicates a single precision literal constant for example In common decimal notation, that will 1256(double), 1145F (float) , 1788888(extended double)
c) C++ Character literal:
An ASCII (American Standard code for information interchange) characters enclosed within the single quotes are called character literal. E. g. “a”, “9”,”^” are called character literals.
Additionally, a character literals can be preceded by L, as in L “b” this is spoken as a wide character literal. Wide character literal support language character sets, such as Chinese and Japanese, in which some of the character value cannot be represented within a single char.
Special character set (escape sequence)- when normal character of proceeded with a /(back slash), they work in different way. These are called escape sequence.
\n – New Line
\t -horizontal tab
\””- double quotes
They can be represented using literal constants.
d) C++ String literal:
C++ String literal constant is composed of zero or one characters enclosed in double quotation marks. Non printable characters can be represented by their underlying escape sequence. A sting literal can extend across multiple lines. A backslash as the last character on a line indicates the string literal is continued on the next line. All string literals are terminated by null.
”- null string
‘a’- string containing single character
e) C++ Boolean literals:
Boolean literals constants have only two values i.e. Either true (non zero) of false(zero) value.