From 7144d80e4f6e90bf82986c48492e3cf0a8072dfa Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Sun, 5 Feb 2017 11:07:05 +0100
Subject: Better error checking (avoid a div-by-0)

---
 histogram.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/histogram.cpp b/histogram.cpp
index a12cd75..2a275e7 100644
--- a/histogram.cpp
+++ b/histogram.cpp
@@ -68,7 +68,13 @@ int main(int argc,char **argv){
 	}
 
 	if(nbins<1){
-		cerr<<"Invalid number of bins '"<<nbins<<"'"<<endl;
+		cerr<<"histogram: Invalid number of bins '"<<nbins<<"'"<<endl;
+		usage();
+		return 1;
+	}
+
+	if(havebounds&&high<=low){
+		cerr<<"histogram: high <= low"<<endl;
 		usage();
 		return 1;
 	}
@@ -112,6 +118,11 @@ int main(int argc,char **argv){
 	histogram[binidx]=tally;
 	if(tally>maxtally)maxtally=tally;
 
+	if(maxtally==0){
+		cerr<<"histogram: No data in range"<<endl;
+		return 1;
+	}
+
 	char fullbar[BARWIDTH+1];
 	memset(fullbar,'#',BARWIDTH);
 	fullbar[BARWIDTH]='\0';
-- 
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