C     Solution of problem 9, page 175, of Nyhoff and Leestma.  
C     The values of three real numbers are check to see if the
C     could represent the sides of triangle.  If so, further tests
C     are done to see if the sides correspond to an equilateral, 
C     isosceles, or scalene triangle.
C
C     Note that the problem states that an isosceles triangle has "at
C     least two sides equal".  This definition would imply that an
C     equilateral triangle is also an isosceles triangle.  However, we
C     will use the definition that an isosceles triangle has two, and
C     only two, sides equal.
C
C     We won't worry about non-positive numbers (though it would be
C     best to do so).
C
C     John Schneider
C     CptS 203, HW 3, problem 1
C--------------------------------------------------------------------------

      program tritst
      implicit none

      real a, b, c
      logical triang, equil, isos, scal

      data triang, equil, isos, scal/4*.false./

      print *, 'Enter three lengths.'
      read *, a, b, c

      if ((a + b .gt. c) .or. (a + c .gt. b) .or. (b + c .gt. a))  then
         triang = .true.
         if (a .eq. b .and. a .eq. c) then
            equil = .true.
         else if (a .eq. b .or. a .eq. c .or. b .eq. c) then
            isos = .true.
         else
            scal = .true.
         endif
      endif

      print *, 'triang is: ',triang
      print *, 'equil is: ',equil
      print *, 'isos is: ',isos
      print *, 'scal is: ',scal

      stop
      end