!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! This is a program which allows the user to compute   !
! the hypotenuse of any number of right triangles.     !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 program p6
  implicit none
  real::base,altitude,hypotenuse,pythagoras
  logical::user_wants_another
  call greeting()
  do
   call read_base_altitude(base,altitude)
   hypotenuse = pythagoras(base,altitude)
   call write_base_altitude_hypotenuse(base,altitude,hypotenuse)
   if ( .not. user_wants_another() ) exit
  end do
  call good_bye()
 end program

 subroutine greeting()
! prints opening message
!! ADDITIONAL STATEMENTS NEEDED HERE
 end subroutine

 subroutine read_base_altitude(b,h)
! output condition: b > 0 and h > 0
! prompts the user to enter positive values for base and height of a right
! triangle.  Continues to query user until positive values are obtained.
!! ADDITIONAL STATEMENTS NEEDED HERE
 end subroutine

 subroutine write_base_altitude_hypotenuse(base,altitude,hypotenuse)
  real,intent(in)::base,altitude,hypotenuse
! input condition: all actual arguments are positive, and are less than 100
! output condition: an appropriate summary is written to the screen
! with two decimal place accuracy
!! ADDITIONAL STATEMENTS NEEDED HERE
 end subroutine

 real function pythagoras(a,b)
! input condition: a > 0 and b > 0 
! output condition: the square of the function value
! is the sum of the squares of a and b
  real,intent(in)::a,b
!! ADDITIONAL STATEMENTS NEEDED HERE
 end function

 logical function user_wants_another()
! queries the user
! output condition: whether the user wants to work another problem
!! ADDITIONAL STATEMENTS NEEDED HERE
 end function

 subroutine good_bye()
! prints closing message
!! ADDITIONAL STATEMENTS NEEDED HERE
 end subroutine