Program g01hcfe

!     G01HCF Example Program Text

!     Mark 28.3 Release. NAG Copyright 2022.

!     .. Use Statements ..
      Use nag_library, Only: g01hcf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: prob, rho
      Integer                          :: df, ierr, ifail
      Character (1)                    :: tail
!     .. Local Arrays ..
      Real (Kind=nag_wp)               :: a(2), b(2)
!     .. Executable Statements ..
      Write (nout,*) 'G01HCF Example Program Results'
      Write (nout,*)

!     Skip heading in data file
      Read (nin,*)

!     Display titles
      Write (nout,*)                                                           &
        ' A(1)         B(1)       A(2)        B(2)        DF  RHO     TAIL P'
      Write (nout,*)

d_lp: Do
        ierr = 0
        a(1:2) = 0.0_nag_wp
        b(1:2) = 0.0_nag_wp

        Read (nin,Fmt='(a1)',Advance='no',Iostat=ierr) tail

!       Read parameter values
        Select Case (tail)
        Case ('l','L')
          Read (nin,*,Iostat=ierr) df, rho, b(1), b(2)
        Case ('c','C')
          Read (nin,*,Iostat=ierr) df, rho, a(1), b(1), a(2), b(2)
        Case ('u','U')
          Read (nin,*,Iostat=ierr) df, rho, a(1), a(2)
        Case Default
          Write (nout,*) 'Invalid problem specification in data file'
          Exit d_lp
        End Select

        If (ierr/=0) Then
          Exit d_lp
        End If

!       Calculate probability
        ifail = 0
        prob = g01hcf(tail,a,b,df,rho,ifail)

!       Display results
        Select Case (tail)
        Case ('l','L')
          Write (nout,99999,Advance='no') '-Inf', b(1), '-Inf', b(2)
        Case ('u','U')
          Write (nout,99998,Advance='no') a(1), 'Inf', a(2), 'Inf'
        Case ('c','C')
          Write (nout,99997,Advance='no') a(1), b(1), a(2), b(2)
        End Select

        Write (nout,99996) df, rho, tail, prob
      End Do d_lp

99999 Format (1X,2(A4,8X,E11.4,1X))
99998 Format (1X,2(E11.4,2X,A3,8X))
99997 Format (1X,4(E11.4,1X))
99996 Format (I3,1X,F7.4,2X,A1,2X,F8.4)
    End Program g01hcfe