update

basic_content/pointer_refer/copy_construct.cpp

@@ -0,0 +1,35 @@
+/**
+ * @file copy_construct.cpp
+ * @brief g++ -o copy_construct copy_construct.cpp -fno-elide-constructors
+ * -fno-elide-constructors选项(关闭返回值优化)
+ * @author 光城
+ * @version v1
+ * @date 2019-08-09
+ */
+
+#include <iostream>
+using namespace std;
+
+class Copyable {
+public:
+    Copyable(){}
+    Copyable(const Copyable &o) {
+        cout << "Copied" << endl;
+    }
+};
+Copyable ReturnRvalue() {
+    return Copyable(); //返回一个临时对象
+}
+void AcceptVal(Copyable a) {
+
+}
+void AcceptRef(const Copyable& a) {
+
+}
+
+int main() {
+    cout << "pass by value: " << endl;
+    AcceptVal(ReturnRvalue()); // 应该调用两次拷贝构造函数
+    cout << "pass by reference: " << endl;
+    AcceptRef(ReturnRvalue()); //应该只调用一次拷贝构造函数
+}