Add reverse iterator and const reverse iterator

HenryRLee · Feb 9, 2019 · 607f102 · 607f102
1 parent f12ea00
commit 607f102
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Showing 2 changed files with 34 additions and 3 deletions.
diff --git a/include/fenwick/fenwick.h b/include/fenwick/fenwick.h
@@ -65,12 +65,25 @@ class fenwick {
   iterator begin() noexcept { return iterator(*this, 0); };
   const_iterator begin() const noexcept { return const_iterator(*this, 0); };
 
-  iterator end() noexcept { return iterator(*this, size_ - 1); };
-  const_iterator end() const noexcept { return const_iterator(*this, size_ - 1); };
+  iterator end() noexcept { return iterator(*this, size_); };
+  const_iterator end() const noexcept { return const_iterator(*this, size_); };
 
   const_iterator cbegin() const noexcept { return begin(); }
   const_iterator cend() const noexcept { return end(); }
 
+  reverse_iterator rbegin() noexcept { return reverse_iterator(end()); };
+  const_reverse_iterator rbegin() const noexcept {
+    return const_reverse_iterator(cend());
+  };
+
+  reverse_iterator rend() noexcept { return reverse_iterator(begin()); };
+  const_reverse_iterator rend() const noexcept {
+    return const_reverse_iterator(cbegin());
+  };
+
+  const_reverse_iterator crbegin() const noexcept { return rbegin(); }
+  const_reverse_iterator crend() const noexcept { return rend(); }
+
   /*
    * Capacity
    */

diff --git a/test/iterator.cc b/test/iterator.cc
@@ -13,6 +13,14 @@ TEST(IteratorTest, BeginEnd) {
   fenwick<int>::const_iterator cit;
   cit = tree.cbegin();
   cit = tree.cend();
+
+  fenwick<int>::reverse_iterator rit;
+  rit = tree.rbegin();
+  rit = tree.rend();
+
+  fenwick<int>::const_reverse_iterator crit;
+  crit = tree.crbegin();
+  crit = tree.crend();
 }
 
 TEST(IteratorTest, Iterate) {
@@ -28,10 +36,20 @@ TEST(IteratorTest, Iterate) {
   }
 
   c = 0;
-
   for (auto it = tree.cbegin(); it != tree.cend(); it++, c++) {
     ASSERT_EQ(c, *it);
   }
+
+  ASSERT_EQ(4, *tree.rbegin());
+  c = 4;
+  for (auto it = tree.rbegin(); it != tree.rend(); it++, c--) {
+    ASSERT_EQ(c, *it);
+  }
+
+  c = 4;
+  for (auto it = tree.crbegin(); it != tree.crend(); it++, c--) {
+    ASSERT_EQ(c, *it);
+  }
 }
 
 }