2.2.1.1 Integer Constants

An integer constant is a whole number with no decimal point. It can have a leading sign and is interpreted as a decimal number. Integer constants take the following form:

snn

s

Is an optional sign.

nn

Is a string of decimal digits. Any leading zeros are ignored.

Rules and Behavior

A minus sign must appear before a negative integer constant, whereas a plus sign is optional before a positive constant (an unsigned constant is assumed to be positive).

Except for a leading algebraic sign, an integer constant cannot contain any character other than the numerals 0 through 9.

The ranges for the integer data types are shown in Section E.3.

The value of an integer constant is normally INTEGER*2, INTEGER*4, or INTEGER*8 (Alpha only). If a value is within INTEGER*2 range, it is treated as an INTEGER*2 value; if a value is outside INTEGER*2 range, but within INTEGER*4 range, it is treated as an INTEGER*4 value, and so forth.

Examples

The following examples show valid and invalid integer constants:

You can use integer constants to assign values to data. The following table shows assignments to different data and lists the integer and hexadecimal values in the data:

Fortran Assignment    Integer Value in Data    Hexadecimal Value in Data

LOGICAL*1 X
INTEGER*1 X

X = -128                         -128                 '80'X
X =  127                          127                 '7F'X
X =  255                           -1                 'FF'X

LOGICAL*2 X
INTEGER*2 X

X = 255                           255                   'FF'X
X = -32768                     -32768                 '8000'X
X = 32767                       32767                 '7FFF'X
X = 65535                          -1                 'FFFF'X

For More Information:

• On integer constants used in expressions, see Section 2.3.1.2.

• On specifying integer constants in octal form, see Sections 2.2.1.4 and A.5.