99 lines
3.4 KiB
Fortran
99 lines
3.4 KiB
Fortran
! This is a fortran95 implementation of the game of tic-tac-toe.
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! - Objective was to use less than 100 lines.
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! - No attention has been devoted to efficiency.
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! - Indentation by findent: https://sourceforge.net/projects/findent/
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! - This is free software, use as you like at own risk.
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! - Compile: gfortran -o tictactoe tictactoe.f90
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! - Run: ./tictactoe
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! Comments to: wvermin at gmail dot com
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module tic
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implicit none
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integer :: b(9)
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contains
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logical function iswin(p)
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integer,intent(in) :: p
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iswin = &
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all(b([1,2,3])==p).or.all(b([4,5,6])==p).or.all(b([7,8,9])==p).or.&
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all(b([1,4,7])==p).or.all(b([2,5,8])==p).or.all(b([3,6,9])==p).or.&
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all(b([1,5,9])==p).or.all(b([3,5,7])==p)
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end function iswin
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subroutine printb(mes)
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character(len=*) :: mes
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integer :: i,j
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character :: s(0:2) = ['.','X','O']
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print "(3a3,' ',3i3)",(s(b(3*i+1:3*i+3)),(j,j=3*i+1,3*i+3),i=0,2)
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if(mes /= ' ') print "(/,a)",mes
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end subroutine printb
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integer recursive function minmax(player,bestm) result(bestv)
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integer :: player,bestm,move,v,bm,win=1000,inf=100000
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real :: x
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if (all(b .ne. 0)) then
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bestv = 0
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else
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bestv = -inf
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do move=1,9
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if (b(move) == 0) then
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b(move) = player
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if (iswin(player)) then
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v = win
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else
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call random_number(x)
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v = -minmax(3-player,bm) - int(10*x)
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endif
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if (v > bestv) then
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bestv = v
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bestm = move
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endif
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b(move) = 0
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if (v == win) exit
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endif
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enddo
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endif
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end function minmax
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end module tic
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program tictactoe
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! computer: player=1, user: player=2
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use tic
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implicit none
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integer :: move,ios,v,bestmove,ply,player=2,k,values(8)
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integer,allocatable :: seed(:)
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call date_and_time(values=values)
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call random_seed(size=k)
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allocate(seed(k))
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seed = values(8)+1000*values(7)+60*1000*values(6)+60*60*1000*values(5)
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call random_seed(put=seed)
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mainloop: do
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b = 0
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call printb('You have O, I have X. You enter 0: game ends.')
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plyloop: do ply=0,4
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if (player == 2 .or. ply >0 ) then ! user move
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write(*,"(/,a)",advance='no'),'Your move? (0..9) '
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getloop: do
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readloop: do
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read (*,*,iostat=ios),move
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if (ios == 0 .and. move >= 0 .and. move <= 9) exit readloop
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write(*,"(a)",advance='no'),'huh? Try again (0..9): '
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enddo readloop
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if ( move == 0) exit mainloop
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if (b(move) == 0) exit getloop
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write(*,"(a)",advance='no'),'Already occupied, again (0..9): '
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enddo getloop
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b(move) = 2
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if(iswin(2)) then ! this should not happen
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call printb('***** You win *****')
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exit plyloop
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endif
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endif
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v = minmax(1,bestmove) ! computer move
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b(bestmove) = 1
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if(iswin(1)) then
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call printb('***** I win *****')
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exit plyloop
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endif
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write(*,"(/,a,i3)"), 'My move: ',bestmove
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call printb(' ')
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enddo plyloop
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if(ply == 5) write(*,"('***** Draw *****',/)")
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player = 3-player
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enddo mainloop
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end program
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