support bazel complie this project and format code.

basic_content/const/extern_const/BUILD

@@ -0,0 +1,14 @@
+# please run `bazel run basic_content/const/extern_const:const_file1` and `# please run `bazel run basic_content/const/extern_const:file`
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "const_file1",
+    srcs = ["const_file1.cpp", "const_file2.cpp"],
+    copts = ["-std=c++11"]
+)
+
+cc_binary(
+    name = "file",
+    srcs = ["file1.cpp", "file2.cpp"],
+    copts = ["-std=c++11"]
+)

basic_content/const/extern_const/const_file1.cpp

@@ -1 +1 @@
-extern const int ext=12;
+extern const int ext = 12;

basic_content/const/extern_const/const_file2.cpp

@@ -1,11 +1,8 @@
-#include<iostream>
+#include <iostream>
 /**
  * by 光城
  * compile: g++ -o file const_file2.cpp const_file1.cpp
  * execute: ./file
  */
 extern const int ext;
-int main(){
-
-    std::cout<<ext<<std::endl;
-}
+int main() { std::cout << ext << std::endl; }

basic_content/const/extern_const/file1.cpp

@@ -1 +1 @@
-int ext;
+int ext;

basic_content/const/extern_const/file2.cpp

@@ -1,11 +1,8 @@
-#include<iostream>
+#include <iostream>
 /**
  * by 光城
  * compile: g++ -o file file2.cpp file1.cpp
  * execute: ./file
  */
 extern int ext;
-int main(){
-
-    std::cout<<(ext+10)<<std::endl;
-}
+int main() { std::cout << (ext + 10) << std::endl; }