50 lines
2.1 KiB
Groff
50 lines
2.1 KiB
Groff
00900 .PR POINT .PR
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01000 .BEGIN #PRINT FIRST THOUSAND PRIME NUMBERS#
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01010 .INT THOUSAND = 320;
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01020 .INT THIRTY = 30; #ACCORDING TO NUMBER THEORY, THE 30TH PRIME > SQRT(THE 1000TH PRIME)#
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01030 .LOC [1:THOUSAND] .INT P; # TABLE TO CONTAIN PRIMES #
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01040 .BEGIN # FILL TABLE P; P[K] WILL BE THE K'TH PRIME #
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01050 P[1] := 2; # THE ONLY EVEN PRIME #
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01060 .LOC .INT J := 1; # ODD NUMBER, TO BE INCREMENTED AND TESTED FOR PRIMENESS #
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01070 .LOC .INT ORD := 1;
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01080 #.INVARIANT P[ORD]**2 > J #
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01090 .LOC .INT SQUARE := 4;
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01100 #.INVARIANT SQUARE = P[ORD]**2 #
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01110 .LOC [1:THIRTY] .INT MULT;
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01120 #.INVARIANT MULT[N] IS A MULTIPLE OF P[N] FOR 1<=N<ORD #
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01130 .FOR K .FROM 2 .TO THOUSAND
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01140 .DO .LOC .BOOL JPRIME;
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01150 .WHILE
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01160 J:=J+2; .WHILE SQUARE<=J .DO MULT[ORD]:=SQUARE; ORD+:=1; SQUARE:=P[ORD]**2 .OD;
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01170 #.ASSERT MULT[ORD] <= J #
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01180 JPRIME := .TRUE;
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01190 .FOR N .FROM 2 .TO ORD-1 .WHILE JPRIME
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01200 .DO # MAKE JPRIME=(P[N] IS NOT A FACTOR OF J) #
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01210 .REF .INT MULTN = MULT[N];
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01220 .WHILE MULTN<J
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01230 .DO MULTN+:=P[N] .OD;
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01240 #.ASSERT J <= MULT[N] < J+P[N] #
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01250 JPRIME := J/=MULTN
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01270 .OD;
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01280 .NOT JPRIME
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01290 .DO .SKIP .OD;
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01300 P[K] := J
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01310 .OD
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01320 .END;
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01330 .BEGIN # PRINT TABLE P ON 5 PAGES, EACH CONTAINING 4 COLUMNS WITH 50 CONSECUTIVE PRIMES #
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01340 PRINT(("TABLE OF FIRST ", THOUSAND, " PRIMES", NEWLINE));
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01350 .INT COLUMNS = 4, LINES = 50;
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01360 .FOR PAGE
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01370 .WHILE .INT K = (PAGE-1)*COLUMNS*LINES+1; K<=THOUSAND
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01380 .DO # PRINT 1 PAGE #
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01390 PRINT (("PAGE ", PAGE, NEWLINE));
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01400 .FOR L .FROM K .TO K+LINES-1 .WHILE L<=THOUSAND
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01410 .DO # PRINT 1 LINE #
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01420 .FOR M .FROM L .BY LINES .TO L+LINES*(COLUMNS-1) .WHILE M<=THOUSAND
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01430 .DO PRINT(P[M]) .OD;
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01440 PRINT(NEWLINE)
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01450 .OD;
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01460 PRINT(NEWPAGE)
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01470 .OD
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01480 .END
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01490 .END
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