do until（〜が満たされるまで繰り返す）構造の例

  do
    ...
    if(条件) exit
   (...)
  end do

例．自然数をその合計がNを超えるまで加えるプログラム

program main
  !
  ! Sample program of DO ... END_DO
  ! Cal. of 1+2+3+...
  !  
  implicit none
  integer :: n
  integer :: sum,counter

  write(*,*) 'Input N'
  write(*,*) 'N = ?'
  read(*,*) n

  sum=0
  counter=0

  do
    counter=counter+1
    sum=sum+counter
    if(sum>n) exit
  end do

  write(*,*) 'Sum up to',counter
  write(*,*) 'sum =',sum

end program main

実行結果