From f882ea84dd356fd39d78f4136ceed190eae3fe6b Mon Sep 17 00:00:00 2001
From: Cody Boone Ferguson <53008573+xexyl@users.noreply.github.com>
Date: Thu, 19 Oct 2023 05:19:58 -0700
Subject: [PATCH] Fix infinite loop in 1989/ovdluhe

As Landon said it is a bug (after I asked about it) I have fixed it.
Without this fix the program printed the same thing over and over again
in some cases. The problem was a for() loop that didn't always have the
pointer incremented. It looks like I could have got away with just
updating the increment part of the loop but I didn't do that as I didn't
see it at first.

The optimiser was disabled. That might not be strictly necessary but I
had it disabled for a time so I have kept it disabled.

Also I removed my name in the README.md: this was missed when the much
better idea of a general thanks file was come up with. When testing the
fix I came across part of my name which made me check. I have not yet
typo/format checked this file or any of 1989 so that was not done. That
might or might not happen in part or in whole later today but either way
it'll be started soon.
---
 1989/ovdluhe/Makefile      |  2 +-
 1989/ovdluhe/README.md     |  4 ++--
 1989/ovdluhe/ovdluhe.alt.c |  2 +-
 1989/ovdluhe/ovdluhe.c     |  2 +-
 thanks-for-fixes.md        | 12 ++++++++++--
 5 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/1989/ovdluhe/Makefile b/1989/ovdluhe/Makefile
index e8f7941c4..547c1cb8a 100644
--- a/1989/ovdluhe/Makefile
+++ b/1989/ovdluhe/Makefile
@@ -68,7 +68,7 @@ CINCLUDE=
 
 # Optimization
 #
-OPT= -O3
+OPT=
 
 # Default flags for ANSI C compilation
 #
diff --git a/1989/ovdluhe/README.md b/1989/ovdluhe/README.md
index 47cd148e4..1f8b6959a 100644
--- a/1989/ovdluhe/README.md
+++ b/1989/ovdluhe/README.md
@@ -38,8 +38,7 @@ by chance or is killed.
 ### Alternate code:
 
 The author suggested that one varies the definition of `P` from 2 through 10. As
-it's a `#define` it's easy to set up which [Cody Boone
-Ferguson](/winners.html#Cody_Boone_Ferguson) did for us. To use try:
+it's a `#define` it's easy to set up. To use try:
 
 ```sh
 make CFLAGS="-DP=9" clobber alt
@@ -47,6 +46,7 @@ make CFLAGS="-DP=9" clobber alt
 
 Use `ovdluhe.alt` as you would `ovdluhe`.
 
+
 ## Judges' remarks:
 
 Run this program using your favorite text file as input.  Files
diff --git a/1989/ovdluhe/ovdluhe.alt.c b/1989/ovdluhe/ovdluhe.alt.c
index 9aad1945e..d830af7db 100644
--- a/1989/ovdluhe/ovdluhe.alt.c
+++ b/1989/ovdluhe/ovdluhe.alt.c
@@ -20,7 +20,7 @@ main(){ape pe,*ep=a;srand((EP)time((long)E));
 while(((*(ep++)=getchar())!=-A)&&((ep-a)<PE));
 *(ae= --ep)=E;for(ap=E;ap<=P;){APE;if(pe=PA())
 {putchar(pe);if(ap<P){p[ap]=pe;ap++;}else{
-ep=p+A;while(*ep) *(ep-A)= *(ep++); *(ep-A)=pe;}}else break;}}
+ep=p+A;while(*ep) *(ep-A)= *(ep++); *(ep-A)=pe;++ap;}}else break;}}
 PA(){EA ape pe,*ep=a,pa,Ap=E;for(ep=a;ep<ae-P;ep++)
 if(!strncmp(ep,p,ap)){e[*(ep+ap)]++;Ap++;}if(!Ap)return(Ap);
 pa=rand()%Ap+A;pe=~E,Ap=!Ap;while((Ap+=e[++pe])<pa);return(pe);}
diff --git a/1989/ovdluhe/ovdluhe.c b/1989/ovdluhe/ovdluhe.c
index aaf0c3147..139bc6c27 100644
--- a/1989/ovdluhe/ovdluhe.c
+++ b/1989/ovdluhe/ovdluhe.c
@@ -14,7 +14,7 @@ main(){ape pe,*ep=a;srand((EP)time((long)E));
 while(((*(ep++)=getchar())!=-A)&&((ep-a)<PE));
 *(ae= --ep)=E;for(ap=E;ap<=P;){APE;if(pe=PA())
 {putchar(pe);if(ap<P){p[ap]=pe;ap++;}else{
-ep=p+A;while(*ep) *(ep-A)= *(ep++); *(ep-A)=pe;}}else break;}}
+ep=p+A;while(*ep) *(ep-A)= *(ep++); *(ep-A)=pe;++ap;}}else break;}}
 PA(){EA ape pe,*ep=a,pa,Ap=E;for(ep=a;ep<ae-P;ep++)
 if(!strncmp(ep,p,ap)){e[*(ep+ap)]++;Ap++;}if(!Ap)return(Ap);
 pa=rand()%Ap+A;pe=~E,Ap=!Ap;while((Ap+=e[++pe])<pa);return(pe);}
diff --git a/thanks-for-fixes.md b/thanks-for-fixes.md
index bb7b22eb5..d68c11574 100644
--- a/thanks-for-fixes.md
+++ b/thanks-for-fixes.md
@@ -494,8 +494,16 @@ you know how?
 
 ## [1989/ovdluhe](1989/ovdluhe/ovdluhe.c) ([README.md](1989/ovdluhe/README.md]))
 
-Cody provided an [alternate version](1989/ovdluhe/ovdluhe.alt.c) based on the
-author's remarks. See the README.md for details.
+Cody fixed an infinite loop where the program would print the same thing over
+and over again, flooding the screen. The problem is that there was a `for` loop
+that by necessity had to not have an increment stage but only in the `if` path
+(in the loop itself) did the pointer get updated. Looking at the code it might
+be that it can work just as well by adding the increment in the loop itself but
+this was not done.
+
+Cody also provided an [alternate version](1989/ovdluhe/ovdluhe.alt.c) based on the
+author's remarks. See the README.md for details. The fix described above was
+fixed in this version too, after it was discovered and fixed.
 
 
 ## [1989/paul](1989/paul/paul.c) ([README.md](1989/paul/README.md]))