Create learn_move_semantics.cpp

Author: XuhuaHuang

Notes/learn_move_semantics.cpp

@@ -0,0 +1,83 @@
+/*****************************************************************//**
+ * \file   learn_move_semantics.cpp
+ * \brief  Brief introduction in move semantics in C++ with
+ * move constructor (rvalue reference)
+ * Compiler g++ optimizes the behaviour of the program
+ * by bypassing all the copying and moving
+ * 
+ * To compile on Windows:
+ * $ g++ -o move.exe .\learn_move_semantics.cpp -std=c++11
+ * $ .\move.exe
+ * 
+ * \author Xuhua Huang
+ * \date   October 2021
+ *********************************************************************/
+
+#include <iostream> // std::cout
+#include <stdlib.h> // system()
+
+/**
+ * Class HasPtrMem Definition.
+ * Stands for "Has Pointer Member"
+ */
+class HasPtrMem
+{
+public:
+	/* Default Constructor */
+	HasPtrMem() : ptr(new int(0)) {
+		std::cout << __func__ << " at line: " << __LINE__ << "\n"
+			<< "Default Construct: " << ++n_cstr << std::endl;
+	}
+
+	/* Copy Constructor */
+	HasPtrMem(const HasPtrMem& rhs) : ptr(new int(*rhs.ptr)) {
+		std::cout << __func__ << " at line: " << __LINE__ << "\n"
+			<< "Copy Constructor: " << ++n_cptr << std::endl;
+	}
+
+	/* Move Constructor */
+	HasPtrMem(HasPtrMem&& rhs) : ptr(rhs.ptr) {
+		rhs.ptr = nullptr; // void the right-hand-side object internal pointer
+		std::cout << __func__ << " at line: " << __LINE__ << "\n"
+			<< "Move Constructor: " << ++n_mvtr << std::endl;
+	}
+
+	/* Destructor */
+	~HasPtrMem() {
+		delete ptr;
+		std::cout << __func__ << " at line: " << __LINE__ << "\n"
+			<< "Destructor: " << ++n_dstr << std::endl;
+	}
+
+	/* Definition of static integer members. */
+	static int n_cstr; // number of times default constructor called
+	static int n_cptr; // number of times copy constructor called
+	static int n_mvtr; // number of times move constructor called
+	static int n_dstr; // number of times destructor called
+// private:
+	int* ptr;
+};
+
+/* Define static variables for class hasPtrMem */
+int HasPtrMem::n_cstr = 0;
+int HasPtrMem::n_cptr = 0;
+int HasPtrMem::n_mvtr = 0;
+int HasPtrMem::n_dstr = 0;
+
+HasPtrMem getTemp() {
+	HasPtrMem temp;
+	std::cout << "Resource from " << __func__ << ": "
+		<< _HEX << temp.ptr << std::endl;
+
+	return temp;
+}
+
+int main(void)
+{
+	HasPtrMem h = getTemp();
+	std::cout << "Resource from " << __func__ << ": "
+		<< _HEX << h.ptr << std::endl;
+
+	system("pause");
+	return 0;
+}