Better error checking (avoid a div-by-0)

1 files changed, 12 insertions, 1 deletions

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';