diff --git a/cpp/2203/220303-CN.cpp b/cpp/2203/220303-CN.cpp
new file mode 100644
index 0000000..3315a04
--- /dev/null
+++ b/cpp/2203/220303-CN.cpp
@@ -0,0 +1,6 @@
+/**
+ * Refer: 220208.cpp
+ *
+ * 258. Add Digits
+ * Given an integer `num`, repeatedly add all its digits until the result has only one digit, and return it.
+ */
\ No newline at end of file