From 531d6d070827ba95a30dc2ddee85cea228f17461 Mon Sep 17 00:00:00 2001
From: wolf <wolf@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Thu, 5 Jul 2001 07:52:02 +0000
Subject: [PATCH] Add constructors to classes, where C++ requires us to do so.

git-svn-id: https://svn.dealii.org/trunk@4817 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/examples/step-4/step-4.cc | 15 +++++++++++++++
 deal.II/examples/step-5/step-5.cc |  7 +++++++
 deal.II/examples/step-6/step-6.cc |  2 ++
 deal.II/examples/step-7/step-7.cc |  8 ++++++++
 4 files changed, 32 insertions(+)

diff --git a/deal.II/examples/step-4/step-4.cc b/deal.II/examples/step-4/step-4.cc
index 893a55f477..1998d4dfc2 100644
--- a/deal.II/examples/step-4/step-4.cc
+++ b/deal.II/examples/step-4/step-4.cc
@@ -124,10 +124,23 @@ class LaplaceProblem
 				 // side with only one parameter,
 				 // namely the point where we want to
 				 // evaluate the function.
+				 //
+				 // Note that the C++ language forces
+				 // us to declare and define a
+				 // constructor to the following
+				 // classes even though they are
+				 // empty. This is due to the fact
+				 // that the base class has no default
+				 // constructor (i.e. one without
+				 // arguments), even though it has a
+				 // constructor which has default
+				 // values for all arguments.
 template <int dim>
 class RightHandSide : public Function<dim> 
 {
   public:
+    RightHandSide () : Function<dim>() {};
+    
     virtual double value (const Point<dim>   &p,
 			  const unsigned int  component = 0) const;
 };
@@ -138,6 +151,8 @@ template <int dim>
 class BoundaryValues : public Function<dim> 
 {
   public:
+    BoundaryValues () : Function<dim>() {};
+    
     virtual double value (const Point<dim>   &p,
 			  const unsigned int  component = 0) const;
 };
diff --git a/deal.II/examples/step-5/step-5.cc b/deal.II/examples/step-5/step-5.cc
index 4ebba492a3..dbe1414ac9 100644
--- a/deal.II/examples/step-5/step-5.cc
+++ b/deal.II/examples/step-5/step-5.cc
@@ -98,10 +98,17 @@ class LaplaceProblem
 				 // information from the ``value''
 				 // function as well will be explained
 				 // below when assembling the matrix.
+				 //
+				 // The need to declare a seemingly
+				 // useless default constructor exists
+				 // here just as in the previous
+				 // example.
 template <int dim>
 class Coefficient : public Function<dim> 
 {
   public:
+    Coefficient ()  : Function<dim>() {};
+    
     virtual double value (const Point<dim>   &p,
 			  const unsigned int  component = 0) const;
     
diff --git a/deal.II/examples/step-6/step-6.cc b/deal.II/examples/step-6/step-6.cc
index c0e2ede8cd..71bbe914e6 100644
--- a/deal.II/examples/step-6/step-6.cc
+++ b/deal.II/examples/step-6/step-6.cc
@@ -140,6 +140,8 @@ template <int dim>
 class Coefficient : public Function<dim> 
 {
   public:
+    Coefficient () : Function<dim>() {};
+    
     virtual double value (const Point<dim>   &p,
 			  const unsigned int  component = 0) const;
     
diff --git a/deal.II/examples/step-7/step-7.cc b/deal.II/examples/step-7/step-7.cc
index c8bbcc6337..0f13486717 100644
--- a/deal.II/examples/step-7/step-7.cc
+++ b/deal.II/examples/step-7/step-7.cc
@@ -180,11 +180,19 @@ const double SolutionBase<dim>::width = 1./3.;
 				 // respective virtual member
 				 // functions in the ``Function'' base
 				 // class.
+				 //
+				 // Just as in previous examples, we
+				 // are forced by the C++ language
+				 // specification to declare a
+				 // seemingly useless default
+				 // constructor.
 template <int dim>
 class Solution : public Function<dim>,
 		 protected SolutionBase<dim>
 {
   public:
+    Solution () : Function<dim>() {};
+    
     virtual double value (const Point<dim>   &p,
 			  const unsigned int  component = 0) const;
     virtual Tensor<1,dim> gradient (const Point<dim>   &p,
-- 
2.39.5