CODEWITHSUNDEEP
ioterminalfortran
Sooraj Soman
Sooraj Soman

Reputation: 159

iostat and inputting from terminal

I understand the use of iostat, when we are inputting from terminal how do I make the status io<0 so that the program understands the end of input is reached?

For example in a simple code to find mean:

program mean
implicit none
real :: x
real :: gmean, amean, hmean
real :: summ,pro,invsum
integer :: i, valid
integer :: io, countt

countt=0
valid=0
summ=0
pro=1
invsum=0

do
    read(*,*,iostat=io) x
    if (io<0) exit
    countt=countt+1
    if (io>0) then
        write(*,*) 'error in input..try again !!!'
    else
        write(*,*) 'Input data #.',countt,':',x
        if (x<=0) then
            write(*,*) 'input <=0..ignored !!'
        else
            valid = valid + 1
            summ = summ + x
            pro = pro*x
            invsum = invsum + (1.0/x)
        end if
    end if
end do
if (valid>0) then
    amean=summ / valid
    gmean = pro**(1.0/valid)
    hmean=valid / invsum

    write(*,*) 'number of valid items --->',valid
    write(*,*) 'arithmetic mean --> ',amean
    write(*,*) 'geometric mean --> ',gmean
    write(*,*) 'harmonic mean --> ',hmean
else
    write(*,*) 'no valid inputs !!'
end if
end program mean

When I execute the code everything works fine except it keeps on asking for inputs. I do not understand how to make io<0.

Upvotes: 1

Views: 82

Answers (2)

agentp
agentp

Reputation: 6999

I like to be nice to the user (even if its just me..)

character*80 input
real val
integer stat
input=''
do while(input.ne.'e')
 write(*,'(a)',advance='no')'enter val [e to end]: '
 read(*,'(a)',iostat=stat)input !iostat here to catch ^d and such
 if(stat.ne.0)input='e'
 if(input.ne.'e')then
  read(input,*,iostat=stat)val  !check iostat here
                                !in case user entered some
  if(stat.ne.0)then             !other non-number
   write(*,*)val
  else
   write(*,*)'expected a number'
  endif
 endif
enddo
end

Upvotes: 1

Alexander Vogt
Alexander Vogt

Reputation: 18118

On Unix systems such as Linux and MAC OS, you can use Ctrl-d to signal the end of the file.

On Windows, use Ctrl-z (from here).

This Wikipedia article compares further command line shortcuts on the various operating systems.

Upvotes: 1

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