FIX: Concatenation of Substring Gives Incorrect Results (70243)

MORE INFORMATION

The following sample programs illustrate the problem:

In an IF Statement

                 character r*2 /'AA'/ 
      n=0

      if ('BBB' .gt. r(1:n+2)//'A') then  ! The IF statement should
                                          ! cause 'YES' to be printed,
                                          ! however 'NO' is printed
                                          ! instead.
         write (*,*) 'YES'
      else
         write (*,*) 'NO'
      endif

      if ('BBB' .gt. r(1:2)//'A') then
         write (*,*) 'YES'
      else
         write (*,*) 'NO'
      endif

      end
				

In a Function

      character*4  a
      character*1  b

      a = 'cdef'
      b = 'd'
      i = len(a)
      print *, i
      j = index('ab'//a(1:i),b)  ! The INDEX function should cause '4'
                                 ! to be printed, however other values
                                 ! are generated instead.
      print *, j
      end
				

Assigning the concatenated expression to a temporary character variable and using the temporary variable in the IF statement or function call will prevent the problem from occurring, as illustrated by the following sample programs:

In an IF Statement

      character r*2 /'AA'/ 

      character str*13             ! Declare a temporary variable and
      str = r(1:n+2)//'A'          ! assign the concatenated expression
                                   ! to it.

      n = 0

      if ('BBB' .gt. str) then     ! Use the temporary variable in
                                   ! the IF statement.

         write (*,*) 'YES'
      else
         write (*,*) 'NO'
      endif

      if ('BBB' .gt. r(1:2)//'A') then
         write (*,*) 'YES'
      else
         write (*,*) 'NO'
      endif

      end
				

In a Function

      character*4  a
      character*1  b
      character*12 str    ! Declare a temporary variable.

      a = 'cdef'
      b = 'd'
      i = len(a)
      print *, i
      str = 'ab'//a(1:i)  ! Assign the concatenated expression
                          ! to the temporary variable.

      j = index(str,b)    ! Use the temporary variable in the
                          ! index function.
      print *, j
      end