program enter
! This file: http://ftp.aset.psu.edu/pub/ger/fortran/hdk/enter.f90
!
! Illustrates how to enter a number or assume a default value if only
! the Enter key is pressed.
   implicit none
   character(80) line
   real :: value = 100.0

   line=''

! f0.d is a Fortran 95 feature that means that the output field width
! will be as only as wide as as necessary to accomodaet the value.
   write(*,'(a,f0.0,a)',advance='no') &
         ' Enter a number (or just press Enter for value=',value,'):'

   read(*,'(a)') line
   if(line /= "") read(line,*) value
   write(*,*) 'The number input:',value

end program enter