組み合わせ

１～ｍ迄の数字をｎ個重複しないように並べる。

実行結果 ｍ＝６、ｎ＝３

  1  2  3
  1  2  4
  1  2  5
  1  2  6
  1  3  4
  1  3  5
  1  3  6
  1  4  5
  1  4  6
  1  5  6
  2  3  4
  2  3  5
  2  3  6
  2  4  5
  2  4  6
  2  5  6
  3  4  5
  3  4  6
  3  5  6
  4  5  6
Press any key to continue . . .

Fortran2003 版

    module m_sub
      implicit none
    contains
      recursive subroutine s_cmb(m, n, list)
        integer, intent(in) :: m, n, list(:)
        integer :: i
        if (n == 1) then
          print '(25i3)', list
        else
          do i = list(size(list)) + 1, m
            call s_cmb(m, n - 1, [list, i])
          end do
        end if
        return
      end subroutine s_cmb
      
      subroutine cmb(m, n)
        integer, intent(in) :: m, n
        integer :: i
        do i = 1, m
          call s_cmb(m, n, [i])
        end do
        return
      end subroutine cmb
    end module m_sub

    program combi03
      use m_sub 
      implicit none
      call cmb(6, 3) 
      stop
    end program combi03

FORTRAN77 版

      PROGRAM cmbntn
      PARAMETER(nmax = 6, n = 3)
      INTEGER m(n)
      i = 1
      m(1) = 0
    1 CONTINUE
        IF (m(i) .LT. nmax) THEN
          m(i) = m(i) + 1
          IF (i .EQ. n) THEN 
            PRINT '(25i3)', m
          ELSE
            i = i + 1
            m(i) = m(i - 1) 
          END IF  
        ELSE
          IF (i == 1) GOTO 999 ! exit  
          i = i - 1 
        END IF    
      GOTO 1
  999 STOP
      END