Open Watcom FORTRAN 77 Language Reference

Format
11.7.10.2 Floating-point Editing: F, E, D and G Edit Descriptors
The F, E, D and G edit descriptors describe the editing of real, double precision, complex and double
precision complex data. The I/O list item corresponding to one of these edit descriptors must be of type
real, double precision, complex or double precision complex. On input, the I/O list item will become
defined with a datum whose type is the same as that of the I/O list item. On output, the I/O list item must
be defined with a datum whose type is that of the I/O list item.
11.7.10.3 F Editing
An F edit descriptor has the form Fw.d where w is the field width and d is the number of digits in the
fractional part. The input field consists of an optional sign, followed by a string of digits optionally
containing a decimal point. If the decimal point is omitted, the rightmost d digits with leading zeroes
assumed if necessary, are interpreted as the fractional part of the value represented. An exponent of one of
the following forms may follow.
1. A signed integer constant.
2. An E or D followed by an optionally signed integer constant.
Consider the following example, where the decimal point is omitted. The formula used in the evaluation is:
-d (exponent subfield)
(integer subfield) x 10 x 10
If the specification is F10.8 and the input quantity is 31415E+5 then the following conversion takes place.
-8 5
00031415 x 10 x 10
= .00031415 x 10
5
= 31.415
In other words, the decimal point is assumed to lie to the left of the 8 digits (padded with zeroes on the left)
forming the fractional part of the input value.
The output field produced by an F edit descriptor consists of blanks if necessary followed by a minus sign
if the item in the I/O list is negative or an optional plus sign otherwise, followed by a string of digits
containing a decimal point which represents the magnitude of the I/O list item. The string representing the
magnitude of the I/O list item is modified according to the scale factor and is rounded to d fractional digits.
An optional leading zero is produced only if the magnitude of the I/O list item is less than one. Note that a
leading zero is required if there would otherwise be no digits in the output field.
Example:
PRINT ’(1H)’, 234.43
The output produced by the PRINT statement in the previous example is the string:
Editing 233