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Merge pull request #139 from xexyl/1998/schnitzi

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Fix segfault in 1998/schnitzi
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Landon Curt Noll authored and GitHub committed 2023-03-24 15:57:28 -07:00
2 parents 949d3673d1 b6635064ea
commit f21b6986f6
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1998/schnitzi/.gitignore
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@@ -1,2 +1,4 @@
data
schnitzi
sort
sort.c
1998/schnitzi/Makefile
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@@ -97,7 +97,7 @@ CDEFINE=
# Include files that are needed to compile
#
CINCLUDE=
CINCLUDE= -include stdlib.h
#CINCLUDE= -include stdlib.h
#CINCLUDE= -include stdio.h
#CINCLUDE= -include stdlib.h -include stdio.h
1998/schnitzi/README.md
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@@ -16,6 +16,11 @@
./schnitzi 5 > sort.c
make sort
## Try:
./schnitzi 3 > sort.c
make sort
echo 123 > data
echo 234 >> data
echo 413 >> data
@@ -23,68 +28,78 @@
echo 324 >> data
./sort < data
[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed a segfault in
this entry. The problem was invalid data types. Thank you Cody for your
assistance!
## Judges' comments
This is a beautiful program. How can a program with no conditional
behavior at all have output which depends on anything?
This is a beautiful program. How can a program with no conditional
behavior at all have output which depends on anything?
For hints on deciphering this, see below past the Author's Comments;
they're a nice summary, but they leave the mystery intact.
BTW: the author notes an incredible lipogram story called
[Gadsby](https://www.gutenberg.org/cache/epub/47342/pg47342.txt) which has no
letter E in the story. He did not note this but it has over 50000 (50 thousand)
(!!) words without the letter E which is one of the most common letters!
For hints on deciphering this, see below past the Author's Comments;
they're a nice summary, but they leave the mystery intact.
## Author's comments
In literary circles, there is a poetic form called a "lipogram",
which is a poem in which a specific letter has been distinctly
avoided. This principle can be applied in other ways. For
instance, in this paragraph, the vowel which immediately follows
't' in the alphabet is nowhere to be seen. There is even an
entire novel (E. V. Wright's "Gadsby") in which no word contains
the letter 'e'.
In literary circles, there is a poetic form called a "lipogram",
which is a poem in which a specific letter has been distinctly
avoided. This principle can be applied in other ways. For
instance, in this paragraph, the vowel which immediately follows
't' in the alphabet is nowhere to be seen. There is even an
entire novel (E. V. Wright's "Gadsby") in which no word contains
the letter 'e'.
The IOCCC has been no stranger to this concept. Several winning
entries from years past have accomplished interesting feats while
completely avoiding the use of certain C constructs thought to
be essential (e.g. 1988's robison.c). If you have to ask why they
would do it this way, then this contest just isn't for you.
The IOCCC has been no stranger to this concept. Several winning
entries from years past have accomplished interesting feats while
completely avoiding the use of certain C constructs thought to
be essential (e.g. 1988's robison.c). If you have to ask why they
would do it this way, then this contest just isn't for you.
In continuing with this fine tradition, this program suggests to
the ANSI committee some new practical simplifications for the C
language. For instance, it appears that CONDITIONAL BRANCHING isn't
really necessary. So, we can do away with while, do...while, for,
if/else, switch, ?:, or anything else that might cause any kind of
nondeterministic jump in the code. There's too much uncertainty
in the world anyway.
In continuing with this fine tradition, this program suggests to
the ANSI committee some new practical simplifications for the C
language. For instance, it appears that CONDITIONAL BRANCHING isn't
really necessary. So, we can do away with while, do...while, for,
if/else, switch, ?:, or anything else that might cause any kind of
nondeterministic jump in the code. There's too much uncertainty
in the world anyway.
Function parameters and return types just confuse people anyway, so
get rid of them. Same with local variables. In fact, all you really
need are assignment statements, and maybe one printf() and one goto.
Function parameters and return types just confuse people anyway, so
get rid of them. Same with local variables. In fact, all you really
need are assignment statements, and maybe one printf() and one goto.
This style of programming is also ideal for systems with limited
memory capacity, since the function call stack never goes beyond
a depth of one.
This style of programming is also ideal for systems with limited
memory capacity, since the function call stack never goes beyond
a depth of one.
So what does it do? Give it an integer (1 < n < 27) on the command
line, such as
So what does it do? Give it an integer (1 < n < 27) on the command
line, such as
schnitzi 5
./schnitzi 5
The output will itself be a lipographic program, one which inputs
(in this case) five numbers and prints them out sorted. It sorts
them, however, using only "if/else" statements, without arrays or
looping. To see the resulting program run, redirect the output from
"schnitzi" into another file, like this
The output will itself be a lipographic program, one which inputs
(in this case) five numbers and prints them out sorted. It sorts
them, however, using only "if/else" statements, without arrays or
looping. To see the resulting program run, redirect the output from
"schnitzi" into another file, like this
schnitzi 4 > sort.c
and then compile it.
and then compile it.
Spoilers And Hints:
### Spoilers And Hints:
The big key to this program is figuring out what the names of the
functions ought to be; a bit of research may allow you to guess at
a few crucial ones.
The big key to this program is figuring out what the names of the
functions ought to be; a bit of research may allow you to guess at
a few crucial ones.
The only function ever called is "O", but "O" is just set to point to
other functions all the time. Or, almost all the time.
The only function ever called is "O", but "O" is just set to point to
other functions all the time. Or, almost all the time.
So how does 'h' get set, and what to?
So how does 'h' get set, and what to?
1998/schnitzi/schnitzi.c
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@@ -1,8 +1,8 @@
typedef void e();
e *w,*l,*u,*_o,*j,*t,*O,exit,b,c_,b_,a_,c,a,z_,x_,d,y_,_m;
int q,m,_d,z,k,h,f[99];
char y[26],_p[40][26],_q,r[2],*_,**s,*i,
e *w,*l,*u,*_o,*j,*t,*O,b,c_,b_,a_,c,a,z_,x_,d,y_,_m,n,*h;
int q,m,z,k,f[99];
char y[26],_p[40][26],_q,r[2],*_,**s,*i,*_d,
*x[]= { "\n", ")", "if (", "}\n", ");\n\n", " ", ",&", "\"",
",", " %%d", ";\n\n scanf(\"%%d", "%%d ", "else ", ",", "<",
@@ -52,5 +52,5 @@ void x_(){ O=g; *r=y[k-2]; _=r; j=o_; }
void d (){ O=g; *r=y[k]; _=r; k=k+1; m=k<z; w=_t; l=p_; j=p; }
void y_(){ O=g; *r=x[17][1]+k; _=r; j=q_; }
void r_(){ O=_b; _=x[17]; s=(char**)_d; s=s+1; i=*s; q=0; }
main(int v,char **c){ O=r_; _d=c;
main(int v,char **V){ O=r_; _d=V;
x: (O)(); goto x; }
bugs.md
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@@ -315,6 +315,27 @@ type).
# 1998
## [1998/schnitzi](1998/schnitzi/schnitzi.c) ([README.md](1998/schnitzi/README.md))
### Status: INABIAF - please do not fix
If you get the compiler warning:
warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
11 | void g(){ O=j; printf(_); }
| ^~~~~~
please do NOT change it! Doing so will break the generated output.
Another warning to ignore is:
warning: assignment to 'char *' from incompatible pointer type 'char **' [-Wincompatible-pointer-types]
55 | main(int v,char **c){ O=r_; _d=c;
| ^
Please do not change this either.
# 2000