From 3f56f36dfb2f38cd5b99488fb6b1346985585476 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Mon, 18 Mar 2019 21:22:39 -0700
Subject: [PATCH] Modulo (%) wrapping of negative numbers behaves differently
 on different platforms. This fixes that.

---
 conway.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/conway.c b/conway.c
index 396c0f0..d191130 100644
--- a/conway.c
+++ b/conway.c
@@ -6,10 +6,10 @@
 #include <termbox.h>
 #include <unistd.h>
 
-#define CELL(cells, x, y) cells[((y) % H)*W + ((x) % W)]
+#define CELL(cells, x, y) cells[(((y)+H) % H)*W + (((x)+W) % W)]
 
 static char rules[2][9] = {{0,0,0,1,0,0,0,0,0}, {0,0,1,1,0,0,0,0,0}};
-static int W, H, DEAD = 0, ALIVE = 7;
+static unsigned int W, H, DEAD = 0, ALIVE = 7;
 
 static void update(const char *cells, char *future_cells)
 {