support bazel complie this project and format code.

learn_class/modern_cpp_30/reference/lifetime.cpp

@@ -0,0 +1,71 @@
+//
+// Created by light on 19-12-15.
+//
+
+#include <iostream>
+#include "shape.h"
+
+using namespace std;
+
+class result {
+public:
+    result() { puts("result()"); }
+
+    ~result() { puts("~result()"); }
+};
+
+result process_shape(const shape &shape1, const shape &shape2) {
+    puts("process_shape()");
+    return result();
+}
+
+
+class Base {
+public:
+    Base() {
+        cout << "Base()" << endl;
+    }
+
+    ~Base() {
+        cout << "~Base()" << endl;
+    }
+};
+
+class Derived : public Base {
+public:
+    Derived() {
+        cout << "Derived()" << endl;
+    }
+
+    ~Derived() {
+        cout << "~Derived()" << endl;
+    }
+};
+
+string f() { return "abc"; }
+
+void g() {
+    const string &s = f();       // still legal?
+    cout << s << endl;
+}
+
+Derived factory() {
+    return Derived();
+}
+
+int main() {
+    process_shape(circle(), triangle());
+    cout << endl;
+    // 临时对象延迟
+//    result &&r = process_shape(circle(), triangle());
+    // 临时对象延迟只对rvalue有用，而对xvalue无用！
+//    result &&r = std::move(process_shape(circle(), triangle()));
+
+//   const Base &b1 = factory();
+
+    Base *b1 = new Derived;
+    delete b1;
+    cout<<endl;
+    Derived d;
+    Base &b2 =d;
+}