magnus@THEP.LU.SE (Magnus Olsson) (07/23/90)
The current debate about 'The CS "religion"' and structurde programming
made me think of the following text which was floating around on the CS
department's VAX a few year ago. A few comments may be in order:
Nothing is known about the author. "Tom A. Crona" is a pseudonym used
by some local hackers at the time.
TLTH is the student union at the Lund Institute of Technology (LTH) -
the program was obviously written by a non-engineer.
The MTH$RANDOM function in the second program returns a random real between
0 and 1.
The English may not be perfect, but English is (presumably) not the
author's native tounge.
The article consists of three programs. All of them compile and run under
VAX/VMS.
Have fun!
Magnus
___________________________BORED-1.FOR_______________________________________
C BORED BY PASCAL?
C ================
C PASCAL IS DESIGNED SO THAT YOU DON'T HAVE TO THINK
C WHILE PROGRAMMING. THIS IS GOOD FOR BEGINNERS BUT WILL
C BECOME A LITTLE BORING AFTER A WHILE.
C THIS LITTLE PROGRAM WAS WRITTEN TO DEMONSTRATE A
C NICE FEATURE OF FORTRAN: THE POSSIBILITY OF WRITING
C I N T E R E S T I N G CODE.
C IF THIS PROGRAM WERE WRITTEN IN PASCAL, IT WOULD BE QUITE
C BANAL AND EASILY UNDERSTANDABLE EVEN TO THE AVERAGE TLTH
C MEMBER. THAT WOULD BE NO FUN, HOWEVER.
C
C NOTE THE FOLLOWING NICETIES:
C * THE ABSENCE OF SENSIBLE COMMENTS-REAL PROGRAMMERS UNDERSTAND
C FORTRAN BETTER THAN ENGLISH!
C * THE ARITHMETIC IF-STATEMENTS (ADDING NICE FLAVOUR TO
C THE CODE)
C * THE WONDERFULLY CONCISE VARIABLE NAMES
C * THE H-FORMAT FOR ALPHANUMERIC OUTPUT ( A LIVING FOSSIL
C FROM THE HAPPY DAYS OF THE PUNCHED CARD)
C * THE NICE SPAGHETTI STRUCTURE - STRUCTURED PROGRAMMING
C IS ONLY FOR AMATEURS AND OLD LADIES
C
C A SMALL REWARD IS OFFERED TO ANYBODY ABLE TO SAY WHAT
C THIS PROGRAM DOES (WITHOUT ACTUALLY RUNNING IT)
C SEND YOUR ANSWERS TO TOM A.CRONA,
C DEPARTMENT OF COMMUTER SCIENCE
C AND NUMERICAL SYNTHESIS,
C UNIVERSITY OF LUND
C
C PLEASE NOTE THAT THIS PROGRAM IS NOT IN ANY WAY PATHOLOGICAL
C BUT A PERFECTLY NORMAL EXAMPLE OF WHAT PROGRAMMING WAS LIKE
C BACK IN THE GOLDEN DAYS WHEN COMPUTERS WERE COMPUTERS AND
C PROGRAMMERS WERE PROGRAMMERS...
10 WRITE (*,487)
READ (*,*) N
IF (N) 10,10,30
30 I1=2
97 I2=0
60 J=MOD(N,I1)
IF (J) 40,50,40
50 I2=I2+1
N=N/I1
GOTO 60
40 IF (I2-1) 70,80,90
70 I1=I1+2
IF (I1-4) 120,135,120
135 I1=3
120 IF (I1-N) 97,97,3
3 WRITE (*,65)
READ (*,*) I3
IF (I3) 3,130,10
130 STOP
80 WRITE (*,855) I1
GOTO 70
90 WRITE (*,930) I1,I2
GOTO 70
487 FORMAT (8H NUMBER?/)
65 FORMAT (20H CONTINUE? (1=Y,0=N)/)
855 FORMAT (I5)
930 FORMAT (I5,3H **,I5)
C BE A CREATIVE PROGRAMMER - USE FORTRAN
C (C) SFRGOD (The Society For Revival of the Good Old
C Days), Fortran section, 1984
END
____________________________BORED-2.PAS_________________________________________
{ BORED BY PASCAL? part 2
==========================
In this degenerate age of the toy computer (by some weak souls
called "personal computer" or something like that) everyone learns
programming in kindergarten or at least in high school (if there's
any difference between those school forms). For this activity, a
language called BASIC is used almost exclusively. BASIC is rather
like a small subset of FORTRAN with many of its good features
amputated but with all of its drawbacks. Anyway, you can write
all kinds of programs in BASIC, and since it (fortunately!) lacks
any trace of structured constructs it promotes creative programming
the same way FORTRAN does and you get programmers who THINK while
they're programming.
When these persons start a higher education, they are forced
to write their programs in a "language" called Pascal and are
thereby quickly converted into well-adapted quiche eaters without
a trace of originality. This paper was written to point out a method
of solving this problem.
Actually, you don't have to learn Pascal at all - it's much easier
to write your programs in BASIC and then translate them directly
into Pascal. As an example, consider the following program. It was
originally written in BASIC on a ZX80 (Yecch!) and then transformed
into syntactically perfect Pascal during the pause between two
lectures.
Most Pascal addicts turn away in disgust when seeing the words
GOTO and LABEL, but there's absolutely no reason to discriminate
these constructs - after all they're a part of the language (if that's
not too strong a word to use about Pascal). Why should any programmer
reject what is good enough for the compiler? Besides, the GOTO was
there first - structured programming is a much later (and unnecessary)
addition.
By following this recipe, the young, undestroyed programmers can
continue writing their programs in BASIC, avoid learning more
Pascal than absolutely necessary and at the same time satisfy the
Pascal buffs of the university. }
PROGRAM NIM (INPUT,OUTPUT);
{(c) Tom A. Crona 1984}
LABEL 70,90,150,230,280,370,400,460,470,520,540,800,810,820;
VAR J,S1,D,E,H,R,K : INTEGER; { WHO NEEDS FANCY LONG VARIABLE NAMES?}
A,B : ARRAY [0..3] OF INTEGER;
C : ARRAY [0..3,0..3] OF INTEGER;
FUNCTION MTH$RANDOM(VAR SEED:INTEGER):REAL; EXTERNAL;
BEGIN
WRITELN ('******* NIM *******');
WRITELN ('I HOPE YOU KNOW THE RULES OF NIM.');
WRITELN ('ANYWAY I''M NOT GOING TO RECITE THEM...');
WRITELN ('ENTER RANDOM SEED');
READ(S1);
70:FOR D:=0 TO 3 DO
A[D]:=TRUNC(MTH$RANDOM(S1)*15+1);
90:FOR D:=0 TO 3 DO
WRITELN (D+1,':',A[D]:2);
IF A[0]+A[1]+A[2]+A[3]>0 THEN GOTO 150;
WRITELN ('*I WON*');
GOTO 540;
150:WRITELN ('WHICH PILE?');
READ (D);
IF (D<1) OR (D>4) THEN GOTO 800;
WRITELN ('HOW MANY?');
READ (E);
IF (E<1) OR (E>A[D-1]) THEN GOTO 810;
A[D-1]:=A[D-1]-E;
D:=-1;
230:D:=D+1;
IF D=4 THEN GOTO 460;
FOR E:=0 TO 3 DO
B[E]:=A[E];
280:B[D]:=B[D]-1;
IF B[D]<0 THEN GOTO 230;
FOR E:=0 TO 3 DO
BEGIN
H:=B[E];
R:=16;
FOR J:=0 TO 3 DO
BEGIN
C[J,E]:=0;
R:=R DIV 2;
IF H<R THEN GOTO 370;
C[J,E]:=1;
H:=H-R;
370:END;
END;
E:=-1;
400:E:=E+1;
H:=C[E,0]+C[E,1]+C[E,2]+C[E,3];
IF H MOD 2>0 THEN GOTO 280;
IF E<3 THEN GOTO 400;
A[D]:=B[D];
GOTO 90;
460:D:=-1;
470:D:=D+1;
IF D=4 THEN GOTO 520;
IF A[D]=0 THEN GOTO 470;
A[D]:=A[D]-TRUNC(MTH$RANDOM(S1)*A[D]+1);
GOTO 90;
520:WRITELN ('YOU WON.');
540:WRITELN ('ENTER 1 IF YOU WISH TO CONTINUE, 0 OTHERWISE');
READ (K);
IF K=1 THEN GOTO 70;
GOTO 820;
800:WRITELN ('THERE IS NO SUCH PILE, STUPID!!!');
GOTO 150;
810:WRITELN ('TRYING TO CHEAT, EH?');
GOTO 150;
820:END.
______________________________BORED-3.COB__________________________________
* BORED BY PASCAL? part 3
* =======================
* With the advent of Pascal, the art of writing interesting code is quickly
* dying out among the younger programmers. I must confess that Pascal has
* made it possible for (almost) everyone to write working programs,
* but it also acts to stifle the true creativity expressed when writing
* (and trying to debug) self-modifying, spaghetti-structured programs
* written in any of the REAL programming languages. The only hope of
* rescue for the "lost generation" of brand-new Pascal "programmers" is
* to learn another language which is better suited for REAL programming.
* In the previous articles of this series we have discussed
* (i) the advantages of real, old-fashioned FORTRAN (not that miserable
* pseudo-Pascal known as FORTRAN 77)
* (ii)the possibility of writing your programs in BASIC and then translating
* them directly into Pascal.
* Some people may be repelled by the short and concise notation of these
* languages - they are suffering from the illusion that a program has
* to be self-explanatory so that every idiot can understand it.
* (in fact it's advantageous to write incomprehensible program since in
* that case you (and not your competitors) will be called in to modify
* it when it's found out that the program won't function because the
* problem was incorrectly stated.)
* There is a cure even for these unfortunate people, however. It's called
* COBOL. The most distinct feature of this language is that it's extremely
* verbose - in fact COBOL is more like a subset of English than a
* programming language!
* While this will (probably) take care of the need for documentation,
* COBOL still has the properties that encourage creative programming,
* like for example:
*
* + The total absence of any "structured" language elements
* + The lack of local variables forcing you to remember all the
* variables you're using (good for your memory if it's a long program)
* + The possibility of writing subroutines with multiple entry and
* exit points (not even BASIC has this last feature!)
* + The ALTER statement for writing self-modifying code (see below)
* + The good old GO TO statement enabling you to give the program
* any kind of structure you like.
*
* You should not be frightened by the fact that COBOL is said to be a
* language for commercial programming. Below is a pure computational
* program (it solves one of those nasty cubic equations)
* written in COBOL which functions quite excellently. (Besides, I have
* met programmers who actually write accounting programs in Algol...)
*
* Since the reader may not be acquainted with the semantics of COBOL,
* I have departed from my holy principles and inserted some comments
* into the code.
IDENTIFICATION DIVISION.
PROGRAM-ID. SOLVE-CUBIC.
AUTHOR. TOM A CRONA.
INSTALLATION. LDC.
DATE-WRITTEN. OCTOBER 22,1984.
DATE-COMPILED. OCTOBER 22,1984.
SECURITY. NONE.
ENVIRONMENT DIVISION.
CONFIGURATION SECTION.
SOURCE-COMPUTER. VAX.
OBJECT-COMPUTER. VAX.
SPECIAL-NAMES.
DECIMAL-POINT IS COMMA.
DATA DIVISION.
* If you think the variable declarations in Pascal are long and tedious,
* have a look at this:
WORKING-STORAGE SECTION.
77 ROOT-1 PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 ROOT-2 PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 EPS PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 X PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 OLD-X PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 LAST-X PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 NEW-X PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 Y PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 Y1 PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 Y2 PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 TEMP PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 TEMP2 PICTURE S999V9(9) USAGE IS COMPUTATIONAL.
77 EDITED-NBR PICTURE ---9,9(9) USAGE IS DISPLAY.
77 ITERATIONS PICTURE 99 USAGE IS COMPUTATIONAL.
* I'm not going to tell you what all this means - consult the nearest
* COBOL reference manual.
PROCEDURE DIVISION.
COMPUTE-ROOTS. DISPLAY "THIS PROGRAM SOLVES 63x^3-9x^2-7x+1=0".
COMPUTE EPS = 10 ** -5.
PERFORM SOLVE THROUGH END-SOLVE MOVE LAST-X TO ROOT-1.
* This is the COBOL equivalent of a subroutine call - and you specify both
* entry and exit points yourself!
ALTER SKIP TO PROCEED TO ELIMINATE-1.
* The above statement is a real goodie - it changes the GO TO END-FUNC below
* to GO TO ELIMINATE-1.
PERFORM SOLVE THROUGH END-SOLVE MOVE LAST-X TO ROOT-2.
ALTER SKIP TO PROCEED TO ELIMINATE-2.
PERFORM SOLVE THROUGH END-SOLVE.
DISPLAY "NO MORE ROOTS".
STOP RUN.
SOLVE. MOVE -1 TO OLD-X MOVE ALL ZEROES TO LAST-X, ITERATIONS.
LOOP. MOVE OLD-X TO X PERFORM COMPUTE-FUNCTION THROUGH END-FUNC
MOVE Y TO Y1.
MOVE LAST-X TO X PERFORM COMPUTE-FUNCTION THROUGH END-FUNC
MOVE Y TO Y2.
IF OLD-X - LAST-X IS LESS THAN EPS AND GREATER THAN - EPS
GO TO END-SOLVE.
SUBTRACT OLD-X FROM LAST-X GIVING TEMP.
SUBTRACT Y1 FROM Y2 GIVING TEMP2.
MULTIPLY Y2 BY TEMP DIVIDE TEMP2 INTO TEMP.
SUBTRACT TEMP FROM LAST-X GIVING NEW-X.
MOVE LAST-X TO OLD-X MOVE NEW-X TO LAST-X.
ADD 1 TO ITERATIONS.
* This way of writing aritmetical statements is peculiar to COBOL.
* You are permitted to write COMPUTE NEW-X = LAST-X -
* ( LAST-X - OLD-X ) / ( Y2 - Y1 ) instead, but that's no sport!
IF ITERATIONS IS GREATER THAN 20 DISPLAY "NO ROOT FOUND"
STOP RUN.
IF Y2 IS LESS THAN - EPS OR GREATER THAN EPS GO TO LOOP.
END-SOLVE. MOVE LAST-X TO EDITED-NBR DISPLAY "X=", EDITED-NBR.
* Numbers are formatted for output by moving them to special "edited"
* variabels like EDITED-NBR.These variables are defined by special
* PICTURE clauses in the DATA DIVISION (if that makes you any wiser,
* you don't need to read the rest)
COMPUTE-FUNCTION. MULTIPLY 7 BY X GIVING Y
SUBTRACT 1 FROM Y MULTIPLY X BY Y MULTIPLY 9 BY Y.
SUBTRACT 7 FROM Y MULTIPLY X BY Y ADD 1 TO Y.
SKIP. GO TO END-FUNC.
* This statement is altered twice: first to GO TO ELIMINATE-1
* and then to GO TO ELIMINATE-2. This self-modifying feature makes it
* possible to write very elegant programs and is a real challenge to
* any creative programmer.
ELIMINATE-2. SUBTRACT ROOT-2 FROM X GIVING TEMP
DIVIDE TEMP INTO Y.
ELIMINATE-1. SUBTRACT ROOT-1 FROM X GIVING TEMP
DIVIDE TEMP INTO Y.
END-FUNC. EXIT.