Xref: utzoo alt.sources:3499 comp.lang.c:37114
Path: utzoo!utgpu!cs.utexas.edu!usc!randvax!ucla-an!hermix!jay
From: jay@hermix.UUCP (Jay Skeer)
Newsgroups: alt.sources,comp.lang.c
Subject: Re: Small introspective program
Message-ID: <217@hermix.UUCP>
Date: 15 Mar 91 21:22:34 GMT
References: <1991Mar10.231230.1301@casbah.acns.nwu.edu> <1991Mar13.001423.5194@Think.COM> <4963@goanna.cs.rmit.oz.au>
Followup-To: alt.sources
Organization: Mark V Systems, Ltd., Encino, Ca
Lines: 40
In-reply-to: ok@goanna.cs.rmit.oz.au's message of 14 Mar 91 00:22:23 GMT

This one is self-recognizing.  I am sure someone can do it shorter.

(Btw, what about lisp's shortest self-repro programs "T", "0", "1", "2", ...)

j'
-------------------
#include <stdio.h>
#define N 18
#define F 8
#define L 80
#define Y Z[k++]
#define P sprintf
char*I="\"%s\",",*B="%s",
M[N*3][L],Z[L],D[N][L]={
"#include <stdio.h>",
"#define N 18",
"#define F 8",
"#define L 80",
"#define Y Z[k++]",
"#define P sprintf",
"char*I=\"\\\"%s\\\",\",*B=\"%s\",",
"M[N*3][L],Z[L],D[N][L]={",
"\"\"},v='\\\\',q='\\\"';",
"main(){int c,i=0,j=0,k,l;",
"for(;i<F;P(M[j++],B,D[i++]));",
"for(i=0;i<N-1;i++,P(M[j++],I,Z))",
"for(k=0,l=0;Z[k]=0,c=D[i][l++];Y=c)",
"((c^v)*(c^q))||(Y=v);",
"for(i=F;i<N;P(M[j++],B,D[i++]));",
"for(i=0;gets(Z);)strcmp(M[i++],Z)&&exit(puts(\"no\"),1);",
"exit(puts(\"yes\"),0);}",
""},v='\\',q='\"';
main(){int c,i=0,j=0,k,l;
for(;i<F;P(M[j++],B,D[i++]));
for(i=0;i<N-1;i++,P(M[j++],I,Z))
for(k=0,l=0;Z[k]=0,c=D[i][l++];Y=c)
((c^v)*(c^q))||(Y=v);
for(i=F;i<N;P(M[j++],B,D[i++]));
for(i=0;gets(Z);)strcmp(M[i++],Z)&&exit(puts("no"),1);
exit(puts("yes"),0);}