program DueNumeri
  implicit none

  real :: x1,x2,y1,y2,xmax,ymax,vmax,xmin,ymin,vmin,vmedia


  write(6,*)'Dammi 4 numeri (x1,x2,y1,y2)'
  read(5,*)x1,x2,y1,y2

  xmax=vmax(x1,x2)
  ymax=vmax(y1,y2)
  write(6,*) 'xmax,ymax',xmax,ymax

  xmin=vmin(x1,x2)
  ymin=vmin(y1,y2)
  write(6,*) 'xmin,ymin',xmin,ymin

  write(6,*)"xmedia = ",vmedia(x1,x2)
  write(6,*)"ymedia = ",vmedia(y1,y2)


  call ord2(x1,x2)
  call ord2(y1,y2)

  write(6,*)'ordinati: ',x1,x2,y1,y2

end program DueNumeri

subroutine ord2(v1,v2)
  ! ordina (crescente) i valori nei due parametri
  implicit none
  real :: v1,v2,t

  if(v1 > v2) then
     t=v1
     v1=v2
     v2=t
  endif
end subroutine ord2


real function vmedia(v1,v2)
  implicit none
  real :: v1,v2

  vmedia=(v1+v2)/2
end function vmedia
!!$

integer function vmax(v1,v2)
  implicit none
  real :: v1,v2

  if(v1 > v2) then
     vmax=v1
  else
     vmax=v2
  endif
end function vmax


real function vmin(v1,v2)
  implicit none
  real :: v1,v2

  if(v1 < v2) then
     vmin=v1
  else
     vmin=v2
  endif
end function vmin