添加设计模式及例子，包括：单例、抽象工厂、适配器、桥接、观察者模式

DesignPattern/AdapterPattern/adapter.h

@@ -0,0 +1,34 @@
+//
+// Created by xiemenghui on 2018/7/20.
+//
+
+#ifndef DESIGNPATTERN_ADAPTER_H
+#define DESIGNPATTERN_ADAPTER_H
+
+#include "target.h"
+#include "adaptee.h"
+
+#ifndef SAFE_DELETE
+#define SAFE_DELETE(p) { if(p){delete(p); (p)=NULL;} }
+#endif
+
+// 电源适配器
+class PowerAdapter : public IRussiaSocket
+{
+public:
+    PowerAdapter() : m_pCharger(new OwnCharger()){}
+    ~PowerAdapter()
+    {
+        SAFE_DELETE(m_pCharger);
+    }
+    void Charge()
+    {
+        // 使用自带的充电器（两脚扁形）充电
+        m_pCharger->ChargeWithFeetFlat();
+    }
+private:
+    // 持有需要被适配的接口对象（自带的充电器）
+    OwnCharger* m_pCharger;
+};
+
+#endif //DESIGNPATTERN_ADAPTER_H