# New extension: Control Flow

**URL:** <https://forum.codecrafters.io/t/new-extension-control-flow/2691>\
**Category:** Announcements\
**Created:** [October 31, 2024, 12:50pm UTC](https://forum.codecrafters.io/t/new-extension-control-flow/2691 "2024-10-31T12:50:47Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\
**Post date:** [October 31, 2024, 12:50pm UTC](https://forum.codecrafters.io/t/new-extension-control-flow/2691/1 "2024-10-31T12:50:47Z")

</div>

The next extension for the Interpreter challenge is now live: **Control Flow**.

 ![Control Flow](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/2X/8/846a361069f35266857b9dcb75ba48610ce52239.jpeg)

This extension builds on the work from the [previous one](https://forum.codecrafters.io/t/new-extension-statements-state/1475) and covers [Chapter 9](https://craftinginterpreters.com/control-flow.html) of the book.

By the end of this extension, your interpreter will be able to handle control flow statements like `if/else` , `while` & `for`, enabling you to print Fibonacci numbers like this:

```java
var a = 0;
var temp;

for (var b = 1; a < 10000; b = temp + b) {
  print a;
  temp = a;
  a = b;
}

```

Please [give this a try](https://app.codecrafters.io/courses/interpreter/overview) and let us know how it can be improved! @ryan-gang (author of this extension), and I will be available here to help out with any tester/instruction issues.