[gtkmm-documentation] exampletreemode: signed/unsigned correction to allow use of auto.

[Murray Cumming <murrayc src gnome org>]

commit a920709ffd1dfbb68094131ef8b20f7c0e77875e
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Mar 17 16:40:23 2017 +0100

    exampletreemode: signed/unsigned correction to allow use of auto.

 .../others/treemodelcustom/exampletreemodel.cc     |   14 +++++++-------
 examples/others/treemodelcustom/exampletreemodel.h |    6 +++---
 2 files changed, 10 insertions(+), 10 deletions(-)
---
diff --git a/examples/others/treemodelcustom/exampletreemodel.cc 
b/examples/others/treemodelcustom/exampletreemodel.cc
index 7f6d1be..818697e 100644
--- a/examples/others/treemodelcustom/exampletreemodel.cc
+++ b/examples/others/treemodelcustom/exampletreemodel.cc
@@ -19,12 +19,12 @@
 #include <iostream>
 #include "exampletreemodel.h"
 
-ExampleTreeModel::GlueItem::GlueItem(int row_number)
+ExampleTreeModel::GlueItem::GlueItem(std::size_t row_number)
 : m_row_number(row_number)
 {
 }
 
-int ExampleTreeModel::GlueItem::get_row_number() const
+std::size_t ExampleTreeModel::GlueItem::get_row_number() const
 {
   return m_row_number;
 }
@@ -149,7 +149,7 @@ bool ExampleTreeModel::iter_next_vfunc(const iterator& iter, iterator& iter_next
 
     //Get the current row:
     const auto pItem = (const GlueItem*)iter.gobj()->user_data;
-    typeListOfRows::size_type row_index = pItem->get_row_number();
+    auto row_index = pItem->get_row_number();
 
     //Make the iter_next GtkTreeIter represent the next row:
     row_index++;
@@ -215,7 +215,7 @@ bool ExampleTreeModel::iter_nth_root_child_vfunc(int n, iterator& iter) const
     //Store the row_index in the GtkTreeIter:
     //See also iter_next_vfunc()
 
-    unsigned row_index = n;
+    const auto row_index = n;
 
     //This will be deleted in the GlueList destructor, when old iterators are marked as invalid.
     auto pItem = new GlueItem(row_index);
@@ -272,7 +272,7 @@ bool ExampleTreeModel::get_iter_vfunc(const Path& path, iterator& iter) const
    //See also iter_next_vfunc()
    //TODO: Store a pointer to some more complex data type such as a typeListOfRows::iterator.
 
-   unsigned row_index = path[0];
+   const auto row_index = path[0];
    auto pItem = new GlueItem(row_index);
 
    //Store the GlueItem in the GtkTreeIter.
@@ -296,7 +296,7 @@ ExampleTreeModel::typeListOfRows::iterator ExampleTreeModel::get_data_row_iter_f
   //Don't call this on an invalid iter.
   const auto pItem = (const GlueItem*)iter.gobj()->user_data;
 
-  typeListOfRows::size_type row_index = pItem->get_row_number();
+  const auto row_index = pItem->get_row_number();
   if( row_index > m_rows.size() )
     return m_rows.end();
   else
@@ -308,7 +308,7 @@ ExampleTreeModel::typeListOfRows::const_iterator ExampleTreeModel::get_data_row_
   //Don't call this on an invalid iter.
   const auto pItem = (const GlueItem*)iter.gobj()->user_data;
 
-  typeListOfRows::size_type row_index = pItem->get_row_number();
+  const auto row_index = pItem->get_row_number();
   if( row_index > m_rows.size() )
     return m_rows.end();
   else
diff --git a/examples/others/treemodelcustom/exampletreemodel.h 
b/examples/others/treemodelcustom/exampletreemodel.h
index 46f3bc3..bc250e3 100644
--- a/examples/others/treemodelcustom/exampletreemodel.h
+++ b/examples/others/treemodelcustom/exampletreemodel.h
@@ -70,11 +70,11 @@ private:
    class GlueItem
    {
    public:
-     GlueItem(int row_number);
-     int get_row_number() const;
+     explicit GlueItem(std::size_t row_number);
+     std::size_t get_row_number() const;
 
    protected:
-     int m_row_number;
+     std::size_t m_row_number;
    };
 
    //Allow the GlueList inner class to access the declaration of the GlueItem inner class.