PROGRAM ERLANG
C
C      This is the root module of the traffic analysis program
C   ERLANG, which solves a number of blocking, queuing, and
C   occupancy problems using the Erlang formulas.
C
C  B. Z. Lederman  I.T.T. World Communications
C
C  Revised 18-Nov-82
C
      REAL*8 QUANT
      LOGICAL*1 ANS
C
      WRITE (5, 10)
   10 FORMAT ('0 This program solves problems using the Erlang',
     1' blocking formulas' / 1X )
   15 WRITE (5, 20)
   20 FORMAT ('0 Enter the factor you want to find:' /
     1'$ TRUNKS, INPUT, BLOCKING, TRAFFIC, OVERFLOW, QUEUE or PROB: ')
      READ (5, 25, END=1800) QUANT
   25 FORMAT (A8)
C
C    Look for a match and call the proper section.
C
      IF (QUANT .EQ. 'BLOCKING') CALL ERLBLO
      IF (QUANT .EQ. 'TRUNKS'  ) CALL ERLTRU
      IF (QUANT .EQ. 'TRAFFIC' ) CALL ERLTRA
      IF (QUANT .EQ. 'INPUT'   ) CALL ERLINP
      IF (QUANT .EQ. 'QUEUE'   ) CALL ERLQUE
      IF (QUANT .EQ. 'PROB'    ) CALL ERLPRO
      IF (QUANT .EQ. 'OVERFLOW') CALL ERLOVE
C
C    Other factors may be added here.
C
      IF (QUANT .EQ. 'STOP'    ) GO TO 1800
      IF (QUANT .EQ. 'EXIT'    ) GO TO 1800
      IF (QUANT .EQ. 'END'     ) GO TO 1800
C
      ANS = 'N'
 1700 WRITE (5, 1710)
 1710 FORMAT (1X /'$ Another Erlang problem [Y/N] ?: ')
      READ (5, 1720, END=1800) ANS
 1720 FORMAT (A1)
      IF ((ANS .EQ. 'Y') .OR. (ANS .EQ. 'y')) GO TO 15
C
 1800 CALL EXIT
C
      END