topic formatted write, allocatable character array in Intel® Fortran Compiler

formatted write, allocatable character array

Alexis_R_ — Wed, 14 Jul 2010 18:27:37 GMT

This program:

[fortran]program test
	implicit none

	character(len=:), allocatable, dimension(:) :: list
	character(len=*), parameter :: header_10 = '         1         2         3         4         5'
	character(len=*), parameter :: header_1  = '12345678901234567890123456789012345678901234567890'
	!

	list = ['pear', '5', 'apple', 'foo', 'J']

	write(*,'(A)')      header_10
	write(*,'(A)')      header_1
	write(*,'(5(A10))') 'pear', '5', 'apple', 'foo', 'J'
	write(*,'(5(A10))') list
	write(*,*)          list

end program[/fortran]

Gives me this output when compiled with ifort linux 11.1.072:

[bash]         1         2         3         4         5
12345678901234567890123456789012345678901234567890
      pear         5     apple       foo         J
     pear      5         apple     foo       J    
 pear 5    applefoo  J  [/bash]

I was hoping that the WRITEing the "list" array with the format specified '5(A10))' would lead to right-hand justification like it does when printing the 'pear', '5', etc. list of strings. However, it appears that the elements of the array were each "allocated" 5 characters ('apple' is the longest word with 5 characters) without right-justification, which wasn't the behaviour I was expecting.

Is there a way for me to achieve right-justification of array items during formatted write? Any workarounds?

formatted write, allocatable character array

Steven_L_Intel1 — Wed, 14 Jul 2010 18:50:09 GMT

Your program is nonstandard - the F2003 rules for the array constructor are that each "ac-value" must be the same length. Intel Fortran has an extension where it picks the longest length. You can't have an array where each element has a different length. To be standard-conforming, you'd have to write:

list = [character(5) :: 'pear', '5', 'apple', 'foo', 'J']

Here's one way to get what you want:

[fortran]program test
 implicit none
 character(len=:), allocatable, dimension(:) :: list
 character(len=*), parameter :: header_10 = ' 1 2 3 4 5'
 character(len=*), parameter :: header_1 = '12345678901234567890123456789012345678901234567890'
 integer i
 !
 list = ['pear', '5', 'apple', 'foo', 'J']
 write(*,'(A)') header_10
 write(*,'(A)') header_1
 write(*,'(5(A10))') 'pear', '5', 'apple', 'foo', 'J'
 write(*,'(5(A10))') (trim(list(i)),i=1,ubound(list,1))
 write(*,*) list
end program[/fortran]

formatted write, allocatable character array

Alexis_R_ — Wed, 14 Jul 2010 19:07:03 GMT

Thanks for your excellent reply.

I had not encountered the construct you use on line 12, which I guess is a one-line implicit loop structure. Does this have a name? I'd like to read up on it!

formatted write, allocatable character array

Steven_L_Intel1 — Wed, 14 Jul 2010 19:28:28 GMT

It's an I/O implied-DO loop, which goes back to F77 at least.

formatted write, allocatable character array

jimdempseyatthecove — Fri, 16 Jul 2010 15:12:05 GMT

>>It's an I/O implied-DO loop, which goes back to F77 at least.
I've used it on Fortran IV (just before F77)