[Android Apps and Games] _darkjoker_:
Intro

Most "bills splitting" apps out there only provide marginally useful information: when you are done using them, you know that A owes you X, B owes you Y and you owe Z to C. Then, probably, A owes something to B as well, and maybe C owes something else to B. Why is it all so complicated? You just wanted to split a few bills!

Chip In provides an alternative to that: follow a few simple steps, and you'll be splitting bills in no time!

First, add as many people as needed (i.e. your friends) using [IMG="'+' icon"]http://fgiobergia.com/images/ext/ic_input_add.png[/IMG]

Then, for each friend, add the bills they paid for (using [img="'coins' icon"]http://fgiobergia.com/images/ext/ic_coins_s.png[/img]). When adding a bill, you can specify both the amount of money spent, and the people splitting that bill: this way, you can even add expenses that only involve a part of the people.

When you are done adding bills, the numbers next to each person is the amount of money they should receive: people with negative balances should each place the displayed amount of money in a common plate. Then, people with positive balances each take the displayed amount of money from the common plate.

Still not clear? Here's a quick example.

The quick example

Alice, Bob and Charlie go for a picnic. Alice brings $15 worth of food, Bob bring $10 worth of beverages, and Charlie brings a $5 cake. Incidentally, only Alice and Charlie eat the cake, since Bob is on a strict diet.

What they do next is use Chip In to split the expenses:

Three people are added (Alice, Bob and Charlie).

A bill is added for Alice: $15 to divide between Alice, Bob and Charlie.

A second bill is then added for Bob: $10 to split among the three of them once again.

Finally, the third bill is added for Charlie: $5 to divide between Alice and Charlie.

At this point, the final balances are:

Alice: +4.17

Bob: +1.67

Charlie: -5.83
​

This means that Charlie needs to take $5.83 out of his pocket and figuratively place it on a common plate: Alice and Bob then proceed to take $4.17 and $1.67 from it. After that, the plate should be empty (actually, because of rounding operations, there may be some cents left/missing!).

Think of what would've happened without Chip In:

Alice would have owed $3.33 to Bob, and $2.5 to Charlie, and would have expected to receive $5 from both Bob and Charlie.

Bob would have owed $5 to Alice, and would have expected $3.33 from both Alice and Charlie.

Charlie would have owed $5 to Alice and $3.33 to Bob, and would have expected $2.5 from Alice.

Sigh.

On the algorithm

This algorithm has been successfully used multiple times to split road trip and holiday bills between three engineer friends (who else could've come up with it?), and was eventually formalized by one of them (i.e. myself) with this app.

The underlying algorithm is actually rather simple, and basically assumes that there's a common fund everybody is using. People paying for something are taking money away from the common fund, and everybody should contribute to the part of the fund that is used to buy something regarding them. Converting those notions to mathematical formulas is almost trivial. But, since you don't need any of this to use the app, I won't bore you with the details!

At first, using Chip In may seem a little counterintuitive, but it takes little time to get the hang of it! And, at that point, splitting bills will be the funniest part of the holiday*!

* Results may vary

Notes

Please keep in mind that, although the app version is 1.x, many new features are yet to come: I am already working on them! If you have any particular request let me know, and I will try to add as many as possible (provided that the ratio #ofRequestsForFeature/ComplexityOfFeature is large enough :D)

Current TODO list

Store sessions on main memory

Parse simple math expressions for the "amount" field

Improve overall graphics

Support multiple languages (EN, IT available so far)

Screenshots

Download

Version 1.0 is available for download on Play Store.

[IMG="Get it on Play Store"]https://developer.android.com/images/brand/en_generic_rgb_wo_60.png[/IMG]