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

A much easier solution IMHO ...................

character(len=8) :: fmt ! format descriptor

fmt = '(I5.5)' ! an integer of width 5 with zeros at the left

i1= 59

write (x1,fmt) i1 ! converting integer to string using a 'internal file'

filename='output'//trim(x1)//'.dat'

! ====> filename: output00059.dat