Open Watcom FORTRAN 77 Language Reference

FORTRAN Statements
Example:
CHARACTER*30 MSG
LOGICAL TRUE
REAL X, Y(10)
DATA X/1.0/, TRUE/.TRUE./, MSG/’ENTER DATA’/
DATA Y/10*5/
An implied-DO list in a DATA statement has the following form:
where:
( dlist, i = m1, m2[, m3] )
dlist
i
m1,m2,m3
is a list of array element names and implied-DO lists.
is the name of an integer variable called the implied-DO-variable.
are each integer constant expressions. The expressions may contain
implied-DO-variables of other implied-DO lists that have this implied-DO list in their
ranges.
The range of the implied-DO list is the list dlist. An iteration count and the value of the
implied-DO-variable are computed from m1,m2 and m3 in the same way as for a DO-loop except that the
iteration count must be positive. An implied-DO-variable does not affect the definition of a variable by the
same name in the same program unit. An implied-DO list is processed as follows. Each item in the
implied-DO list is processed once for each iteration with the appropriate substitution of values for any
occurrence of the implied-DO-variable. The following example initializes the upper right triangle of the
array A.
Example:
DIMENSION A(5,5)
DATA ((A(I,J),J=1,I),I=1,5)/15*0/
Dummy arguments, functions, and entities in blank common are not allowed in nlist. Entities in a
named common block can be initialized only within a block data subprogram.
The following extensions to data initialization are supported by Open Watcom FORTRAN 77.
1. Character constants can initialize a variable of any type. If the item in nlist is of numeric
type and is being initialized with character data, the size of the item in nlist is the maximum
number of characters that can be stored in the space allocated for that item. The rules for
initializing such items, are the same as for items of type character. See the chapter entitled
"Names, Data Types and Constants" on page 151 for the number of bytes required for a
particular data type.
Example:
INTEGER I,J
DATA I/’AA’/,J/’123456’/
In the previous example, I and J each occupy 4 character storage units. I will be initialized
with the characters AA followed by 2 blank characters. J will be initialized with the characters
1234. Note the the character constant initializing J is truncated on the right to the number of
character storage units occupied by J.
DATA Statement 39