support bazel complie this project and format code.

basic_content/friend/BUILD

@@ -0,0 +1,15 @@
+# please run `bazel run basic_content/friend:friend_class`
+# please run `bazel run basic_content/friend:friend_func`
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "friend_class",
+    srcs = ["friend_class.cpp"],
+    copts = ["-std=c++11"]
+)
+
+cc_binary(
+    name = "friend_func",
+    srcs = ["friend_func.cpp"],
+    copts = ["-std=c++11"]
+)

basic_content/friend/friend_class.cpp

@@ -2,27 +2,23 @@
 
 using namespace std;
 
-class A
-{
+class A {
 public:
-    A(int _a):a(_a){};
-    friend class B;
+  A(int _a) : a(_a){};
+  friend class B;
+
 private:
-    int a;
+  int a;
 };
 
-class B
-{
+class B {
 public:
-    int getb(A ca) {
-        return  ca.a; 
-    };
+  int getb(A ca) { return ca.a; };
 };
 
-int main() 
-{
-    A a(3);
-    B b;
-    cout<<b.getb(a)<<endl;
-    return 0;
+int main() {
+  A a(3);
+  B b;
+  cout << b.getb(a) << endl;
+  return 0;
 }

basic_content/friend/friend_func.cpp

@@ -1,33 +1,20 @@
-/**
- * @file friend_func.cpp
- * @brief 友元函数
- * @author 光城
- * @version v1
- * @date 2019-08-06
- */
-
 #include <iostream>
 
 using namespace std;
 
-class A
-{
+class A {
 public:
-    A(int _a):a(_a){};
-    friend int geta(A &ca);  ///< 友元函数
+  A(int _a) : a(_a){};
+  friend int geta(A &ca); ///< 友元函数
 private:
-    int a;
+  int a;
 };
 
-int geta(A &ca) 
-{
-    return ca.a;
-}
+int geta(A &ca) { return ca.a; }
 
-int main()
-{
-    A a(3);    
-    cout<<geta(a)<<endl;
+int main() {
+  A a(3);
+  cout << geta(a) << endl;
 
-    return 0;
+  return 0;
 }