Never used
Fortran.
Think of it as an old-style version of BASIC. WRITE is like PRINTUSING,
with FORMAT being where you specify the print pattern. Any variable whose
name starts with the letters I J K L M or N (alphabetic letters between I
and N (which is the start of "INteger")) is assumed to be an int, unless
you tell it otherwise. Many brands of it require giving a line number to
every line.
Oops!
For FORTRAN, that should read, "like some brands of BASIC, you can skip
assigning line numbers to lines that aren't explicitly referenced."