Convert integers to strings to create output filenames at run time

Question

I have a program in Fortran that saves the results to a file. At the moment I open the file using

OPEN (1, FILE = \'Output.TXT\')

However,

Answer 1

Well here is a simple function which will return the left justified string version of an integer:

character(len=20) function str(k)
!   "Convert an integer to string."
    integer, intent(in) :: k
    write (str, *) k
    str = adjustl(str)
end function str

And here is a test code:

program x
integer :: i
do i=1, 100
    open(11, file='Output'//trim(str(i))//'.txt')
    write (11, *) i
    close (11)
end do
end program x