Fix C++ example namespace

docs/src/userguide/wrapping_CPlusPlus.rst

@@ -75,43 +75,38 @@ and the implementation in the file called :file:`Rectangle.cpp`:
 
     #include "Rectangle.h"
 
-    using namespace shapes;
+    namespace shapes {
 
-    Rectangle::Rectangle(int X0, int Y0, int X1, int Y1)
-    {
+        Rectangle::Rectangle(int X0, int Y0, int X1, int Y1) {
             x0 = X0;
             y0 = Y0;
             x1 = X1;
             y1 = Y1;
         }
 
-    Rectangle::~Rectangle()
-    {
-    }
+        Rectangle::~Rectangle() { }
 
-    int Rectangle::getLength()
-    {
+        int Rectangle::getLength() {
             return (x1 - x0);
         }
 
-    int Rectangle::getHeight()
-    {
+        int Rectangle::getHeight() {
             return (y1 - y0);
         }
 
-    int Rectangle::getArea()
-    {
+        int Rectangle::getArea() {
             return (x1 - x0) * (y1 - y0);
         }
 
-    void Rectangle::move(int dx, int dy)
-    {
+        void Rectangle::move(int dx, int dy) {
             x0 += dx;
             y0 += dy;
             x1 += dx;
             y1 += dy;
         }
   
+    }
+
 This is pretty dumb, but should suffice to demonstrate the steps involved.
 
 Specify C++ language in setup.py