From c5d3e8fa51377b14373c5ed202c0a00bd4b34ef7 Mon Sep 17 00:00:00 2001
From: Jidong Xiao <xiaoj8@rpi.edu>
Date: Thu, 14 Sep 2023 14:36:02 -0400
Subject: [PATCH] notes on curly braces representing empty vector

---
 lectures/02_strings_vectors/README.md | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lectures/02_strings_vectors/README.md b/lectures/02_strings_vectors/README.md
index a6b000b..eafa052 100644
--- a/lectures/02_strings_vectors/README.md
+++ b/lectures/02_strings_vectors/README.md
@@ -77,6 +77,19 @@ Here are several different ways to initialize a vector:
 ```cpp
 std::vector<int> a;
 ```
+
+or, 
+
+```cpp
+std::vector<int> a{};
+```
+
+Here, in C++, a pair of curly braces is used to initialize an empty container. Vector is a type of container, and we will learn other containers later this semester. Interesting trick: if you have a function which has a return type of vector, and in your function body, you want to return an empty vector without specifying a vector name, you can do:
+
+```cpp
+return {};
+```
+
 - This constructs a vector of 100 doubles, each entry storing the value 3.14. New entries can be created using
 push_back, but these will create entries 100, 101, 102, etc.
 ```cpp