Open Watcom FORTRAN 77 Language Reference

Language Reference
Actually, hollerith constants are treated as character constants and can be used wherever a character
constant can be used. Hollerith constants are different from character constants in that a quote is
represented by two quotes in character constants and by a single quote in hollerith constants.
The following are examples of hollerith constants.
5HABCDEFG
10h xxxxx ’44
3.4.10 Hexadecimal Constants (Extension)
Two forms of hexadecimal constant are supported. The first form can only be used in type declaration or
DATA statements. The second form may be used anywhere an integer constant may be used.
The first form of hexadecimal constant consists of the letter Z or z followed by a string of hexadecimal
digits. A hexadecimal digit can be any digit or one of the letters A, B, C, D, E or F (the lower case of
these letters is also acceptable). The actual data is the hexadecimal digits following the letter Z or z.
Hexadecimal constants of this form can only be used in type declaration statements and DATA statements
for initializing memory with binary patterns.
The following are examples of the first form of hexadecimal constant.
z1234
Zac
The first example is equivalent to the binary pattern 0001 0010 0011 0100. The second example is
equivalent to the binary pattern 1010 1100.
The second form of hexadecimal constant consists of an apostrophe followed by any string of hexadecimal
digits followed by an apostrophe and then the letter X or x. A hexadecimal digit can be any digit or one of
the letters A, B, C, D, E or F (the lower case of these letters is also acceptable). The actual data is the
hexadecimal digits placed inside apostrophes.
The following are examples of the second form of hexadecimal constant.
’1234’x
’ac’X
The first example is equivalent to the binary pattern 0001 0010 0011 0100. The second example is
equivalent to the binary pattern 1010 1100.
3.4.11 Octal Constants (Extension)
An octal constant consists of an apostrophe followed by any string of octal digits followed by an
apostrophe and then the letter O or o. An octal digit can be any of the digits 0 through 7. The actual data
is the octal digits placed inside apostrophes. An octal constant may be used anywhere an integer constant
may be used.
156 Constants