This is the self-printing program item.  Post programs that print out their
own source code (in whatever language) here.

23 responses total.

Here's my first example, in C.  Let's see if fronttalk doesn't eat it up....
Hopefully, I didn't make any errors cutting and pasting it.

/*
 *  This is a test.
 */

#include <stdio.h>
#include <stdlib.h>
#define PRT(S)  (void)printf(S, #S)

int
main(void)
{
        PRT("/*\n *  This is a test.\n */\n\n#include <stdio.h>\n#include
        <stdlib.h>\n#define\tPRT(S)\t(void)printf(S,
        #S)\n\nint\nmain(void)\n{\n\tPRT(%s);\n\treturn(EXIT_SUCCESS);\n}\n");
               return(EXIT_SUCCESS);
}

#!/bin/cat

what's the point of #define ing PRT ?

You tell me.  :-)

i guess the # flag assures that everything is printed ? 

Sortof.  It "stringifies" its argument.

i'll have to look at this again when i'm not writing cantus firmi and
memorising terms like "complément circonstanciel de temps".

Take your time.

that's the problem with being a full-time student; there's never enough time
 :(

True.

Google for "quine".

Interesting.  I found this nice page over at Nyx:
http://www.nyx.net/~gthompso/quine.htm

 Well, I was going to enter a null response but there's no easy way to
 do it that I'm aware.  But it would satisfy the requirements.

Ooo...cheater.

 I prefer to think of it as efficiency and elegant simplicity.

The question is, what language is it in?

 it's a quine in just about any shell you care to interpret it with..

I was leading up to a joke about the empty set, but I'll refrain.

Here's one in BASIC.  It has to jump through some hoops to get around 
the inability to escape quotation marks in most BASICs.  I don't have a 
BASIC interpreter handy to test it, but I think it should work:

 10 READ N
 20 READ D$
 30 FOR X = 1 TO (N-2)
 40 READ A$
 50 PRINT X*10 A$
 60 NEXT X
 70 RESTORE
 80 FOR Y = 1 TO N
 90 READ A$
100 PRINT (X+Y)*10 D$ CHR$(34) A$ CHR$(34)
110 NEXT Y
120 DATA 13
130 DATA "DATA "
140 DATA "READ N"
150 DATA "READ D$"
160 DATA "FOR X = 1 TO N"
170 DATA "READ A$"
180 DATA "PRINT X*10 A$"
190 DATA "NEXT X"
200 DATA "RESTORE"
210 DATA "FOR Y = 1 TO N"
220 DATA "READ A$"
230 DATA "PRINT (X+Y)*10 D$ CHR$(34) A$ CHR$(34)"
240 DATA "NEXT Y"

all right ; BASIC

I've already spotted a typo in it.  Line 160 should match line 30, but 
doesn't.

There were a couple of problems with it.  It would also print line 120
as '120 DATA "13"'.  Here's a corrected version; I believe it will work,
but also don't have a BASIC interpreter available.

 10 READ N
 20 READ D$
 30 FOR X = 1 TO N-1
 40 READ A$
 50 PRINT X*10 A$
 60 NEXT X
 70 RESTORE
 80 READ N
 90 PRINT N*10 D$ N
100 FOR Y = 1 TO N
110 READ A$
120 PRINT (N+Y)*10 D$ CHR$(34) A$ CHR$(34)
130 NEXT Y
140 DATA 14
150 DATA "DATA "
160 DATA "READ N"
170 DATA "READ D$"
180 DATA "FOR X = 1 TO N-1"
190 DATA "READ A$"
200 DATA "PRINT X*10 A$"
210 DATA "NEXT X"
220 DATA "RESTORE"
230 DATA "READ N"
240 DATA "PRINT N*10 D$ N"
250 DATA "FOR Y = 1 TO N"
260 DATA "READ A$"
270 DATA "PRINT (N+Y)*10 D$ CHR$(34) A$ CHR$(34)"
280 DATA "NEXT Y"

An interesting post that reminded me of this item:  Self-reproducing 
zip and gzip files:

http://research.swtch.com/2010/03/zip-files-all-way-down.html

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- Backtalk version 1.3.30 - Copyright 1996-2006, Jan Wolter and Steve Weiss