I have an old Fortran 77 code, which I would like to run in a F90-Compiler, and my goal is to change the code as less as possible. It works quite well, but I have some problem with format statements in the code. And I don't understand what's the problem. I work with Eclipse, and gfortran. I use free form.
This compiles fine:
program HelloWorld
400 FORMAT(7HK GAMMA,2X,G13.5,7H P0,2X,G13.5,6H A1,2X,G13.5)
end program
This doesn't compile
program HelloWorld
400 FORMAT(7HK 'GAMMA',2X,G13.5,7H 'P0',2X,G13.5,6H 'A1',2X,G13.5)
1
end program
The Error is
P descriptor needs leading scale factor in format string at (1)
(the error is translated from german, might not be exactly the same words in english) What is wrong?
This also compiles fine:
program HelloWorld
400 FORMAT(7HK GAMMA,2X,G13.5,7H P0, &
2X,G13.5,6H A1,2X,G13.5)
end program
If I add more code to the last code:
program HelloWorld
400 FORMAT(7HK GAMMA,2X,G13.5,7H P0,2X,G13.5,6H A1,2X,G13.5, &
2X,7HK,ALPHA-1,2X,G13.5,7H BETA-4,2X,G13.5 )
end program
it doesn't compile anymore. The error is:
P Edit descriptor expected in the format string* at (1)
whereas the (1) is placed at the third line after the closing bracket.
*I'm not sure about the translation of "format string", as my console is in german.
What is the problem there?
As I write in the comment it looks more like FORTRAN66 than 77 because the Hollerith H
descriptor and data type was used before introducing the CHARACTER
data type to the language. It was also used to assign character data to integer variables, but fortunately that is very rare to encounter. The use as an edit descriptor is however more common, although very obsolete.
It is not clear what you want to achieve, good example of the desired output would be helpful.
Do you meant:
400 FORMAT(7HK GAMMA,2X,G13.5,3H P0,2X,G13.5,3H A1,2X,G13.5)
so that
print 400, 1. ,2. ,3.
outputs
K GAMMA 1.0000 P0 2.0000 A1 3.0000
Or should the P0 and A1 serve as edit descriptors?
What was the original code in the legacy software?
The nH
Hollerith descriptor just outputs n
next characters so it can unintentionally "eat" some of your descriptors and just print them.
That is the problem that causes that your examples do not compile, because the n
before H
is too large and the rest of the format then has no sense.
The next one could be
400 FORMAT(8H 'GAMMA',2X,G13.5,5H 'P0',2X,G13.5,5H 'A1',2X,G13.5)
to print
'GAMMA' 1.0000 'P0' 2.0000 'A1' 3.0000
The effect of the above in Fortran 95 and above is better achieved by
print '(A0,2X,G13.5,A0,2X,G13.5,A0,2X,G13.5)', " 'GAMMA'",1.," 'P0'", 2.0, " 'A1'", 3.0
and maybe you would rather use just:
print '(A0,2X,G13.5,A0,2X,G13.5,A0,2X,G13.5)', "GAMMA",1.,"P0", 2.0, "A1", 3.0
for printing
GAMMA 1.0000 P0 2.0000 A1 3.0000
or even
print *, "GAMMA",1.,"P0", 2.0, "A1", 3.0