! This file: http://ftp.aset.psu.edu/pub/ger/fortran/hdk/ucaseCP.f90
!
! Read a string and convert to upper case.
!  Author: Clive Page <cgp@le.ac.uk>
!---------------------------------------------------------------------
program test_upper
implicit none
character(len=20) :: up, s
write(*,"(1x,A)",advance='no') "Enter string: "
read(*,'(A)') s
write(*,*) 'up = ', up(s)
end program

Character (len=20) Function Up (string)
Character(len=*) string
up =                                                                  &
   transfer(merge(achar(iachar(transfer(string,"x",len(string)))-     &
   (ichar('a')-ichar('A')) ),                                         &
   transfer(string,"x",len(string)) ,                                 &
   transfer(string,"x",len(string)) >= "a" .and.                      &
   transfer(string,"x",len(string)) <= "z"), repeat("x", len(string)))
return
end function