! 例題 7-1  16進数表現 ［文字部分列 ］
PROGRAM ex7_1

  IMPLICIT NONE
  INTEGER :: dec, i
  CHARACTER ( LEN = 1 ) :: h( 0 : 15 ) = (/ '0', '1',  &
                   '2', '3', '4', '5', '6', '7', '8',  &
                   '9', 'a', 'b', 'c', 'd', 'e', 'f' /)
  CHARACTER ( LEN = 8 ) :: hex

  ext: DO
         hex = ' '
         PRINT *, 'Input a positive integer, or 0 to stop: '
         READ *, dec
         IF ( dec <= 0 ) EXIT ext
  hxd:   DO i = 0, 7
           hex( 8 - i : 8 - i ) = h( MOD( dec, 16 ) )
           dec = dec / 16
           IF ( dec == 0 ) EXIT hxd
         END DO hxd
         PRINT '( 1X, A8 )', hex
       END DO ext

END PROGRAM ex7_1