By Liew Hanqing

WHILE most children his age are busy with toys and games, nine-year-old Lim Ding Wen keeps himself busy with his passion - writing computer applications.

His latest achievement - writing an application for the Apple iPhone. The painting program called Doodle Kids allows users to create drawings on their iPhones with different coloured shapes.

Users use their fingers to draw on the iPhone's touchscreen. To clear their screens, users need only to shake their iPhones.

Ding Wen, a Primary 4 student at Lianhua Primary School, wrote the original application on his computer last year, but adapted it for the iPhone only recently.

About two weeks ago, he uploaded the application online for iPhone users to download for free.

The application has since been downloaded more than 4,000 times from the iTunes Store, an online digital media store run by Apple.

More than half of the daily downloads come from the US, according to reports from iTunes e-mailed to him every day.

Ding Wen told The New Paper that he was surprised by the popularity of his application. 'I wrote the program for my younger sisters, who like to draw. But I am happy that people like it.'

His sisters are aged 3 and 5.

He added that he wrote the application in just 'a few days'.

Ding Wen has also started writing a sci-fi game for the iPhone, which he calls 'Invader Wars'.

His father, Mr Lim Thye Chean, 40, the chief technology officer of a tech company, said: 'He told me it was his wish to learn programming so I decided to teach him the basics.'

Ding Wen quickly mastered BASIC, a programming language, then moved on to learn Pascal, reading up voraciously to improve his skills. The stack of programming books by Ding Wen's bedside is telling.

He eventually successfully wrote the Doodle Kids application in Pascal, then adapted it for the iPhone.

Ding Wen said he spends up to two hours every day working on his programming projects. He is familiar with six programming languages, including Pascal, JavaScript and ActionScript.

To date, he has completed about 20 projects, including computer applications, animations and games.

Most of the time, he works on the projects alone with little or no input from his father. They have a small competition going - to see whose program is more popular among downloaders.

Mr Lim has written a similar paint program, called Simple Paint, which can be downloaded free from the iTunes store.

Said Mr Lim: 'Every evening, we check the statistics e-mailed to us to see who has more downloads.'

On most days, father and son are neck-and-neck.

He added that his son has always been good with computers - at the age of two, Ding Wen could already use a mouse to click and select icons on his desktop at home.

An above-average student at school, Ding Wen said he plans to join his school's robotics club.

This article was first published in The New Paper on February 05, 2009.