For instance, an integer variable called IEMPNO might be used in one part of a Fortran subroutine to denote an employee social security number ( ssn ), but during maintenance work on the same subroutine, a programmer might accidentally use the same variable, IEMPNO, for a different purpose, and this could result in a bug that was difficult to trace.
42.
With the inclusion of " Extend mode " in later versions, variable names could be up to 29 characters long, and dot ( . ) was added as a permitted character, but every variable name still had to begin with a letter . ( Before the introduction of Extend mode, white space was not required between variables and other language elements : " " would be interpreted as " " . ) Integer variables ( 16-bit, range-32768 to + 32767 ) were indicated with a % suffix; string variables ( variable length ) were indicated with a $ suffix.
