C-FOCAL,1969

01.11 C THIS PROGRAM COMPUTES THE AVERAGE DELAY (BAR D) IN SECONDS
01.12 C USING C(C,A), THE ERLANG C BLOCKING PROBABILITY.
01.13 A "WHAT IS THE NUMBER OF SERVERS?",C,!
01.14 A "WHAT IS THE LOAD IN ERLANGS?",A,!
01.15 A "WHAT ARE THE TOTAL NUMBER OF CALLS?",TC,!
01.16 IF (2-C)2.11,2.11,7.11

02.11 S B=1./A
02.12 S CINT=FITR(C)
02.13 F D=2.,CINT; DO 6
02.14 GOTO 3.11

03.11 S ERLC=1./(1.+(1.-A/C)*B)
03.12 S H=A*3600./TC
03.13 IF (C-A)4.14,4.11,3.14
03.14 S AVE=ERLC*(H/(C-A))

04.11 T %8.08 "ERLANG C BLOCKING PROBABILITY ",ERLC,!!
04.12 T "AVERAGE DELAY IN SECONDS  ",AVE,!!
04.13 T "AVERAGE CALL HOLDING TIME ",H,"  SECONDS",!!; Q
04.14 T "LOAD EXCEEDS SERVERS"; Q

06.11 S B=(D/A)*(B+1)

07.11 S ERLC=A
07.12 GOTO 3.12

08.11 C THE FORMULA IS GIVEN AS:
08.12 C      AVERAGE DELAY(BAR D)=C(C,A) * H/(C-A)
08.13 C      C = NUMBER OF SERVERS
08.14 C      A = OFFERED LOAD IN ERLANGS
08.15 C      H = AVERAGE HOLDING TIME
08.16 C C(C,A) = ERLANG C BLOCKING PROBABILITY
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