Fix constructor definitions in demos and docs

demos/Functor.cpp

@@ -23,13 +23,9 @@ class Equation {
   double m_x, m_y;
 
   public:
-  Equation(double x, double y) : m_x(x), m_y(y) {}
-  double operator()(double i, double j) {
-    return m_x*i*j + m_y*i*j;
-  }
-  void setX(double x) {
-    m_x = x;
-  }
+    Equation(double x = 0, double y = 0) : m_x(x), m_y(y) {}
+    double operator()(double i, double j) { return m_x * i * j + m_y * i * j; }
+    void setX(double x) { m_x = x; }
 };
 
 int main() {

demos/Jupyter/Intro.ipynb

@@ -427,7 +427,7 @@
     "  double m_x, m_y;\n",
     "\n",
     "  public:\n",
-    "  Equation(double x, double y) : m_x(x), m_y(y) {}\n",
+    "  Equation(double x = 0, double y = 0) : m_x(x), m_y(y) {}\n",
     "  double operator()(double i, double j) {\n",
     "    return m_x*i*j + m_y*i*j;\n",
     "  }\n",

demos/Templates.cpp

@@ -22,15 +22,15 @@ template <class T> class Equation {
   T m_x, m_y;
 
 public:
-  Equation(T x, T y) : m_x(x), m_y(y) {}
+  Equation(T x = 0, T y = 0) : m_x(x), m_y(y) {}
   T operator()(T i, T j) { return m_x * i * i + m_y * j * j; }
 };
 
 template <> class Equation<long double> {
   long double m_x, m_y;
 
 public:
-  Equation(long double x, long double y) : m_x(x), m_y(y) {}
+  Equation(long double x = 0, long double y = 0) : m_x(x), m_y(y) {}
   long double operator()(long double i, long double j) {
     return 2 * m_x * i * i + 2 * m_y * j * j;
   }

docs/userDocs/source/user/UsingClad.rst

@@ -418,7 +418,7 @@ An example that demonstrates the differentiation of functors::
     double m_x, m_y;
   
     public:
-    Equation(double x, double y) : m_x(x), m_y(y) {}
+    Equation(double x = 0, double y = 0) : m_x(x), m_y(y) {}
     double operator()(double i, double j) {
       return m_x*i*j + m_y*i*j;
     }