From 3939a4c4334f56bc43e8b78f229610368aa954ea Mon Sep 17 00:00:00 2001
From: "Coo.King" <39448470+Pega-Stellar@users.noreply.github.com>
Date: Tue, 16 Oct 2018 10:18:59 +0700
Subject: [PATCH] Update index.md (#19051)

---
 .../src/pages/guide/english/cplusplus/compilers/index.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/client/src/pages/guide/english/cplusplus/compilers/index.md b/client/src/pages/guide/english/cplusplus/compilers/index.md
index d1c11bbce1..9d9b0f94a9 100644
--- a/client/src/pages/guide/english/cplusplus/compilers/index.md
+++ b/client/src/pages/guide/english/cplusplus/compilers/index.md
@@ -78,6 +78,15 @@ to compile and execute your code directly, run
 `g++ -o helloWorld helloWorld.cpp; ./helloWorld`
 so when you need to compile and run your code multiple times,
 up arrow-enter 
+
+### Adding Flags
+You can also add flags to the compiler to your custom and favor. For example:
+`g++ -O2 helloWorld.cpp -o helloWorld`
+Some common flags is :
+1. -O2 : Optimize your code, so it may run faster
+2. -std=c++11 : use c++11 instead of c++98 which is defaulted.
+3. -Wall: prompt some warning about some common mistakes which can bug your program.
+4. -Wextra: prompt some extra warning.
 ____________
 
 There are a number of different types of compilers. The two listed are the two that are usually packaged with the Windows