From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 17 Jun 2019 11:27:36 +0000 (+0200)
Subject: com_stats(): Avoid division by zero.
X-Git-Tag: v1.0.1~6
X-Git-Url: http://git.tuebingen.mpg.de/?p=tfortune.git;a=commitdiff_plain;h=278b70e25a37bae191066c4e08f96fd8624f31e4

com_stats(): Avoid division by zero.

If no epigrams are defined yet, the arguments to printf() contain
a division by zero which results in output like:

	average number of epigrams per file     -nan
	average number of tags per epigram.     -nan
	average number of tag recurrence...     -nan

This is not a wrong per se, but it seems to be safer to special case
this and print zero.
---

diff --git a/tfortune.c b/tfortune.c
index 751334d..ec4c323 100644
--- a/tfortune.c
+++ b/tfortune.c
@@ -895,11 +895,11 @@ static int com_stats(void)
 	printf("number of tags..................... %5lu\n", num_tags);
 	printf("number of unique tags.............. %5u\n", num_unique_tags);
 	printf("average number of epigrams per file %8.02f\n",
-		(float)num_epis / num_epi_files);
-	printf("average number of tags per epigram. %8.02f\n",
-		(float)num_tags / num_epis);
-	printf("average number of tag recurrence... %8.02f\n",
-		(float)num_tags / num_unique_tags);
+		num_epi_files > 0?  (float)num_epis / num_epi_files : 0);
+	printf("average number of tags per epigram. %8.02f\n", num_epis > 0?
+		(float)num_tags / num_epis : 0);
+	printf("average number of tag recurrence... %8.02f\n", num_unique_tags > 0?
+		(float)num_tags / num_unique_tags : 0);
 	if (verbose) {
 		printf("\nlinear hashing statistics:\n%s\n", lh_stats);
 		free(lh_stats);