[lmi-commits] [lmi] master b772ca6 2/5: Avert division by zero

[Greg Chicares]

branch: master
commit b772ca60bf377d26b5ca0e09a7be1e58ea5eef5f
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Avert division by zero
---
 report_table.cpp      | 1 +
 report_table_test.cpp | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/report_table.cpp b/report_table.cpp
index 7d41694..e9638f1 100644
--- a/report_table.cpp
+++ b/report_table.cpp
@@ -49,6 +49,7 @@ std::vector<int> apportion(std::vector<int> const& votes, int 
total_seats)
     int const cardinality = lmi::ssize(votes);
     std::vector<int> seats(cardinality);
     int const total_votes = std::accumulate(votes.begin(), votes.end(), 0);
+    if(0 == total_votes) return seats; // Avert division by zero.
     std::priority_queue<std::pair<int,int>> queue;
     for(int j = 0; j < cardinality; ++j)
         {
diff --git a/report_table_test.cpp b/report_table_test.cpp
index b3261c8..580bc8a 100644
--- a/report_table_test.cpp
+++ b/report_table_test.cpp
@@ -118,6 +118,13 @@ void report_table_test::test_apportion()
 
     std::vector<int> const seats2 = {8, 8, 5, 2, 2, 1};
     BOOST_TEST(seats2 == apportion(votes1, 26));
+
+    // Test with zero total votes, to make sure that division by zero
+    // is averted.
+
+    std::vector<int> const votes3 = {0, 0, 0};
+    std::vector<int> const seats3 = {0, 0, 0};
+    BOOST_TEST(seats3 == apportion(votes3, 7));
 }
 
 void report_table_test::test_bloat()