add Composite pattern

composite/Composite.cpp

@@ -0,0 +1,87 @@
+/*
+ * C++ Design Patterns: Composite
+ * Author: Jakub Vojvoda [github.com/JakubVojvoda]
+ * 2016
+ *
+ * Source code is licensed under MIT licence
+ * (for more details see LICENCE)
+ *
+ */
+
+#include <iostream>
+#include <vector>
+
+/*
+ * Component
+ * defines an interface for all objects in the composition
+ * both the composite and the leaf nodes
+ */
+class Component {
+public:
+  virtual Component *getChild(int) { return 0; }
+
+  virtual void add(Component *) { /* ... */ }
+  virtual void remove(int) { /* ... */ }
+
+  virtual void operation() = 0;
+};
+
+/*
+ * Composite
+ * defines behavior of the components having children
+ * and store child components
+ */
+class Composite : public Component {
+public:
+  Component *getChild(int index) {
+    return children.at(index);
+  }
+
+  void add(Component *component) {
+    children.push_back(component);
+  }
+
+  void remove(int index) {
+    children.erase(children.begin() + index);
+  }
+
+  void operation() {
+    for (unsigned int i = 0; i < children.size(); i++) {
+      children.at(i)->operation();
+    }
+  }
+
+private:
+  std::vector<Component *> children;
+};
+
+/*
+ * Leaf
+ * defines the behavior for the elements in the composition,
+ * it has no children
+ */
+class Leaf : public Component {
+public:
+  Leaf(int i) : id(i) {}
+
+  void operation() {
+    std::cout << "Leaf "<< id <<" operation" << std::endl;
+  }
+
+private:
+  int id;
+};
+
+
+int main()
+{
+  Composite composite;
+
+  for (unsigned int i = 0; i < 10; i++) {
+    composite.add(new Leaf(i));
+  }
+
+  composite.operation();
+
+  return 0;
+}