Open Watcom FORTRAN 77 Language Reference

FORTRAN Statements
Example:
IMPLICIT CHARACTER*10 (S-U)
IMPLICIT INTEGER*2 (P)
CHARACTER STRING
INTEGER POINTS
In the above example, the variable STRING is of type character but its length is 1 since it has
appeared in a CHARACTER statement which has a default length of 1. Also, the variable
POINTS is of type integer but its length is 4 since it has appeared in an INTEGER statement
which has a default length of 4.
2. A letter cannot appear more than once as a single letter or be included in a range of letters in all
IMPLICIT statements in a program unit.
3. An IMPLICIT statement applies only to the program unit that contains it.
4. The IMPLICIT statement does not change the type of intrinsic functions.
5. A program unit can contain more than one IMPLICIT statement.
6. Within the specification statements of a program unit, IMPLICIT statements must precede all
other specification statements except PARAMETER statements.
7. The IMPLICIT NONE statement is allowed only once in a program unit. Furthermore, no
other IMPLICIT statement can be specified in the program unit containing an IMPLICIT
NONE statement.
IMPLICIT Statement 91