Fortran by Fortran: The Format statement

One of the things in Fortran I always have some doubt is the format specification fields of FORMAT statement. Time to time I see myself looking for its specification fields. PRINT, WRITE, READ and FORMAT are the ones that uses the formating specifications. Here is the list of the most important ones.

FORMAT SPECIFICATION FIELDS:

Format field	Properties	Data type
Iw[.m]	w - width m - leading zeros	Integer values
Fw.d	w - width d - decimal point precision	Float values
Ew.d[Ee]	w - width d - decimal point precision e - optional exponent width	Float values (Engineering mode)
Ew.d[Ee]	w - width d - decimal point precision e - optional exponent width	Float values (Engineering mode)
Dw.d	w - width d - decimal point precision	Double precision values
Lw	w - width	Logical values
A[w]	w - width	String values
Zw	w - width	Hexadecimal values
Ow[.m]	w - width m - leading zeros	Octal values
"a" or 'a'	a - string sequence	Outputs the string sequence
nX	n - number of spaces	Outputs n space characters
nH	n - number of chars	Hollerith constant - Outputs the next n characters
$		Doesn't output line break

HOW TO USE:

How to use the format statement and its format specification fields? One way you declare a FORMAT statement is something like below:

r FORMAT (f1,f2,...,fn)

r - Label number
f1,f2,...,fn - format specification fields

Its easy to use it, the only thing you must remember is the label number r.

PRINT r,e1,e2,...,en
WRITE (unit, r) e1,e2,...,en
READ r,e1,e2,...,en
READ (unit, r),e1,e2,...,en

Where e1,e2,...,en are expressions matching each one a format specification field.

The other way to declare the format specification fields is explicitly writing it. You change the label number by a quoted format specifications fields like below.

PRINT '(f1,f2,...,fn)',e1,e2,...,en