FORTRAN Reference Manual

Language Elements

FORTRAN Reference Manual—528615-001

2-11

Constants

A constant is an unvarying datum. A constant can be a number, a constant expression,

a complex value, a logical value, or a string of characters.

You can use a PARAMETER statement to create a symbolic name for a constant. See

the PARAMETER Statement on page 7-79.

Arithmetic Constants

Integer, real, double precision, and complex constants are called arithmetic constants.

Integer Constants

You must express an integer constant as a whole number. You can place a minus sign

in front of an integer to indicate a negative number. The following are examples of

integer constants:

123 <-- word integer

-52381 <-- doubleword integer

9814387278 <-- quadrupleword integer

An integer constant is considered to be of the smallest size (INTEGER*2, INTEGER*4,

INTEGER*8) that can contain it.

An integer constant cannot contain a decimal point or a comma. However, you can

make a constant more readable by grouping digits of the constant and separating the

groups with blanks. The compiler ignores the blanks. For example:

9 814 387 278

You can represent an integer constant in octal notation. An octal constant has the

range of a quadrupleword integer and is a string of from 1 to 22 digits—only the digits

0, 1, 2, 3, 4, 5, 6, and 7 are valid—prefixed with a percent sign (%). Precede the

percent sign with a minus sign if the number is negative. The following is an example

of a negative, octal integer.

-%1034621

Real Constants

A real constant is a string of decimal digits that must include a decimal point or an

exponent. It cannot include commas, but you can use embedded spaces for

readability. You can express a real constant as a decimal number. For example:

7.5

-.0001

24578.342