support bazel complie this project and format code.

basic_content/enum/BUILD

@@ -0,0 +1,16 @@
+# please run `bazel run basic_content/enum:classic_practice`
+# please run `bazel run basic_content/enum:tradition_color`
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "classic_practice",
+    srcs = ["classic_practice.cpp"],
+    copts = ["-std=c++11"]
+)
+
+# Don't panic if you get compilation errors, this is what this code demonstrates, as expected.
+cc_binary(
+    name = "tradition_color",
+    srcs = ["tradition_color.cpp"],
+    copts = ["-std=c++11"]
+)