Added composite example.

README.md

@@ -1073,6 +1073,129 @@ objects and compositions uniformly.
 
 #### Programmatic Example
 
+Taking our employees example from above. Here we have different employee types
+
+```cpp
+class Employee
+{
+  public:
+    typedef std::shared_ptr<Employee> ptr_t;
+    virtual std::string getName(void) = 0;
+    virtual void setSalary(float salary) = 0;
+    virtual float getSalary(void) = 0;
+    virtual std::string getRole(void) = 0;
+};
+
+class Developer : public Employee
+{
+  public:
+    Developer(const std::string& name, float salary)
+        : name_(name), salary_(salary), role_("Developer")
+    {
+    }
+
+    std::string getName(void)
+    {
+      return name_;
+    }
+
+    void setSalary(float salary)
+    {
+      salary_ = salary;
+    }
+
+    float getSalary(void)
+    {
+      return salary_;
+    }
+
+    std::string getRole(void)
+    {
+      return role_;
+    }
+
+  private:
+    std::string name_;
+    float salary_;
+    std::string role_;
+};
+
+class Designer : public Employee
+{
+  public:
+    Designer(const std::string& name, float salary)
+        : name_(name), salary_(salary), role_("Designer")
+    {
+    }
+
+    std::string getName(void)
+    {
+      return name_;
+    }
+
+    void setSalary(float salary)
+    {
+      salary_ = salary;
+    }
+
+    float getSalary(void)
+    {
+      return salary_;
+    }
+
+    std::string getRole(void)
+    {
+      return role_;
+    }
+
+  private:
+    std::string name_;
+    float salary_;
+    std::string role_;
+};
+```
+
+Then we have an organization which consists of several different types of employees
+
+```cpp
+class Organization
+{
+  public:
+    void addEmployee(Employee::ptr_t employee)
+    {
+      employees_.push_back(employee);
+    }
+
+    float getNetSalaries(void)
+    {
+      float net = 0;
+      for (auto employee : employees_) {
+        net += employee->getSalary();
+      }
+
+      return net;
+    }
+
+  private:
+    std::vector<Employee::ptr_t> employees_;
+};
+```
+
+Here is how this can be used:
+
+```cpp
+// Prepare the employees.
+Employee::ptr_t jane = std::make_shared<Developer>("Jane Doe", 50000);
+Employee::ptr_t john = std::make_shared<Designer>("John Doe", 45000);
+
+// Add them to the organization.
+Organization org;
+org.addEmployee(jane);
+org.addEmployee(john);
+
+// Get the net salaries.
+std::cout << org.getNetSalaries() << std::endl; // Output: 95000
+```
 
 #### When To Use