iterator,string: add size queries

iterator.hpp

@@ -297,6 +297,11 @@ namespace util {
         iterator begin (void) const { return iterator { value_type {0} }; }
         iterator end   (void) const { return iterator { value_type (m_container.size ()) }; }
 
+        constexpr auto size (void) const noexcept
+        {
+            return std::size (m_container);
+        }
+
     private:
         const ContainerT &m_container;
     };

string.hpp

@@ -127,6 +127,16 @@ namespace util {
         iterator cend (void) const { return { { m_range.cend (), m_range.cend () }, m_separator }; }
         iterator  end (void) const { return { { m_range.cend (), m_range.cend () }, m_separator }; }
 
+        std::size_t
+        size (void) const
+        {
+            return std::count (
+                m_range.begin (),
+                m_range.end (),
+                m_separator
+            ) + 1u;
+        }
+
     private:
         const range_type m_range;
         const value_type m_separator;