support bazel complie this project and format code.

learn_class/modern_cpp_30/reference/shape.h

@@ -0,0 +1,41 @@
+#pragma once
+#include <iostream>
+using namespace std;
+
+class shape {
+public:
+    shape() { cout << "shape" << endl; }
+
+    ~shape() {
+        cout << "~shape" << endl;
+    }
+};
+
+class circle : public shape {
+public:
+    circle() { cout << "circle" << endl; }
+
+
+    ~circle() {
+        cout << "~circle" << endl;
+    }
+};
+
+class triangle : public shape {
+public:
+    triangle() { cout << "triangle" << endl; }
+
+
+    ~triangle() {
+        cout << "~triangle" << endl;
+    }
+};
+
+class rectangle : public shape {
+public:
+    rectangle() { cout << "rectangle" << endl; }
+
+    ~rectangle() {
+        cout << "~rectangle" << endl;
+    }
+};