support bazel complie this project and format code.

practical_exercises/10_day_practice/day2/enum.cpp

@@ -0,0 +1,17 @@
+/* 枚举类型.cpp */
+#include <iostream>
+using namespace std;
+
+enum weekday { s, m, t, w, thu, f, s1 };
+
+int main(int argc, char const *argv[]) {
+  enum weekday wek = s;
+  // weekday wek=s;
+  for (int i = wek; i != f; i++) {
+    cout << i << endl;
+    cout << wek + s << endl;
+    cout << "-------哈哈-------" << endl;
+  }
+  
+  return 0;
+}