PROGRAM QuadraticEquations
!-----------------------------------------------------------------------
! Program to solve a quadratic equation using the quadratic formula.
! Variables used are:
!    A, B, C        : the coefficients of the quadratic equation
!    Discriminant   : the discriminant, B**2 - 4.0*A*C
!    Root_1, Root_2 : the two roots of the equation
!
! Input:  The coefficients A, B, and C
! Output: The two roots of the equation or the (negative) discriminant
!         and a message indicating that there are no real roots
!-----------------------------------------------------------------------

  IMPLICIT NONE
  REAL A, B, C, Discriminant, Root_1, Root_2

  ! Get the coefficients
  PRINT *, "Enter the coefficients of the quadratic equation:"
  READ *, A, B, C

  ! Calculate the discriminant
  Discriminant = B**2 - 4.0*A*C

  ! Check if discriminant is nonnegative.  If it is, calculate and
  ! display the roots.  Otherwise display the value of the discriminant
  ! and a no-real-roots message.
  IF (Discriminant >= 0) THEN
     Discriminant = SQRT(Discriminant)
     Root_1 = (-B + Discriminant) / (2.0 * A)
     Root_2 = (-B - Discriminant) / (2.0 * A)
     PRINT *, "The roots are", Root_1, Root_2
  ELSE
     PRINT *, "Discriminant is", Discriminant
     PRINT *, "There are no real roots"
  END IF

END PROGRAM QuadraticEquations