[hcheng] amazing func pointer for class member func

dev0 · dev0 · commit c21d6ec8468d · 2018-03-12T05:57:54.000-04:00
diff --git a/amazing_polymorphism/amazing_polymorphism_func.cc b/amazing_polymorphism/amazing_polymorphism_func.cc
@@ -0,0 +1,35 @@
+// <Selected Topic in C++> Topic 13 Function Pointers
+#include <iostream>
+#include <vector>
+using namespace std;
+class BaseClass {
+public:
+	int objId;
+	BaseClass(int objId): objId(objId) {}
+	virtual void callBackFun() {
+		cout << "BaseClass callBackFunc " << objId << endl;
+	}
+};
+
+class DerivedClass : public BaseClass {
+public:
+	DerivedClass(int objId) : BaseClass(objId) {}
+	virtual void callBackFun() {
+		cout << "DerivedClass callBackFunc " << objId << endl;
+	}
+};
+
+void commonCallbackFunc(BaseClass *obj, void(BaseClass::*callbackFuncPtr)()) {
+	(obj->*callbackFuncPtr)();
+}
+
+int main(int argc, char** argv) {
+	//vector<BaseClass*> collector = {BaseClass(1), DerivedClass(2)}; // will call vector<T> allocator to allocate memory on heap??
+	vector<BaseClass*> objs = {new BaseClass(1), new DerivedClass(2)};
+	void(BaseClass::*callbackFuncPtr)() = &BaseClass::callBackFun;
+	for (auto ptr : objs) {
+		commonCallbackFunc(ptr, callbackFuncPtr);
+		delete ptr;
+	}
+	return 0;
+}
