update c++

Coding/C++_LR_Value.cpp

@@ -0,0 +1,47 @@
+/*
+ * @Author: [email protected]
+ * @Last Modified time: 2016-08-31 18:57:14
+ */
+
+#include <iostream>
+using namespace std;
+
+class cs
+{
+public:
+    cs(int i): data(i)  { cout << "cs(" << i <<") constructor!" << endl; }
+    ~cs() { cout << "cs destructor,i(" << data << ")" << endl; }
+
+    cs& operator=(const cs& other)
+    {
+        data = other.data;
+        cout << "cs operator=()" << endl;
+        return *this;
+    }
+
+    int get_i() const { return data; }
+    void change(int i)  { data = i; }
+
+private:
+    int data;
+};
+
+cs get_cs()
+{
+    static int i = 0;
+    return cs(i++);
+}
+
+int main()
+{
+    // 合法
+    (get_cs() = cs(2)).change(323);
+    get_cs() = cs(2);// operator=()
+    get_cs().change(32);
+
+    // 右值只能被 const 引用
+    const cs& ref = get_cs();
+    cout << "Here last cs object get from get_cs has not been destructed.\n";
+
+    return 0;
+}