! 例題 5-6  素数表 ［構文名の指定（CYCLE）］
PROGRAM ex5_6

  IMPLICIT NONE
  INTEGER :: n, m, max = 1000, mn

  PRINT '( 1X, I3 )', 2                 ! 2以外の偶数は素数でない

  x: DO n = 3, max, 2
       mn = NINT( SQRT( REAL( n ) ) )
       DO m = 3, mn, 2
         IF ( MOD( n, m ) == 0 ) CYCLE x
       END DO
       PRINT '( 1X, I3 )', n
     END DO x                              ! CYCLE x でここへ飛ぶ

END PROGRAM ex5_6