From 37b4824a62065571ecf8dee3015bb97c8b17932d Mon Sep 17 00:00:00 2001
From: Jonathan Lamothe <jonathan@jlamothe.net>
Date: Fri, 23 Aug 2013 13:07:31 -0400
Subject: [PATCH] make sure the factor is valid (also accept non-base 10
 numbers)

---
 dpu.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/dpu.c b/dpu.c
index aa6fc80..d699d85 100755
--- a/dpu.c
+++ b/dpu.c
@@ -1,3 +1,4 @@
+#include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -7,7 +8,13 @@ int main (int argc, char **argv){
 	FILE *bob,*joe,*moe;
 	int thing, factor, arg;
 	if(argc >= 3){
-		factor = atoi (argv[1]);
+        char *end_char;
+		factor = strtol(argv[1], &end_char, 0);
+        if(!*(argv[1]) || *end_char)
+        {
+            fputs("I can haz number?\n", stderr);
+            return EXIT_FAILURE;
+        }
 		arg = 2;
 	}else{
 		factor = 9;