Access XAMPP Localhost from Internet
First, you need to configure your computer to get a static IP from your router. Instructions for how to do this can be found: here
For example, let's say you picked the IP address 192.168.1.102. After the above step is completed, you should be able to get to the website on your local machine by going to both http://localhost and http://192.168.1.102, since your computer will now always have that IP address on your network.
If you look up your IP address (such as http://www.ip-adress.com/), the IP you see is actually the IP of your router. When your friend accesses your website, you'll give him this IP. However, you need to tell your router that when it gets a request for a webpage, forward that request to your server. This is done through port forwarding.
Two examples of how to do this can be found here and here, although the exact screens you see will vary depending on the manufacturer of your router (Google for exact instructions, if needed).
For the Linksys router I have, I enter http://192.168.1.1/, enter my username/password, Applications & Gaming tab > Port Range Forward. Enter the application name (whatever you want to call it), start port (80), end port (80), protocol (TCP), ip address (using the above example, you would enter 192.168.1.102, which is the static IP you assigned your server), and be sure to check to enable the forwarding. Restart your router and the changes should take effect.
Having done all that, your friend should now be able to access your webpage by going to his web browser on his machine and entering http://IP.address.of.your.computer (the same one you see when you go here ).
As mentioned earlier, the IP address assigned to you by your ISP will eventually change whether you sign offline or not. I strongly recommend using DynDns, which is absolutely free. You can choose a hostname at their domain (such as cuga.kicks-ass.net) and your friend can then always access your website by simply going to http://cuga.kicks-ass.net in his browser. Here is their site again: DynDns
I hope this helps.
I guess you can do this in 5 minute without any further IP/port forwarding, for presenting your local websites temporary.
All you need to do it,
go to http://ngrok.com
Download small tool
extract and run that tool as administrator
Enter command ngrok http 80
You will see it will connect to server and will create a temporary URL for you which you can share to your friend and let him browse localhost or any of its folder.
You can see detailed process here.
How do I access/share xampp or localhost website from another computer