Abstract: A method and computing device is provided for converting between Chinese calendar dates and Julian day numbers in any specified date range using tables stored in the memory of the computing device containing the lengths of the months and which (if any) months are leap months, together with one or more reference pairs of Julian day numbers and Chinese date.

Abstract: A first computing device in the form of a mobile phone is used to initiate a comparison of the entries stored in a contacts store associated with the first device with the entries stored in a contacts store associated with a second device. Mutual contacts are then advised to the second device. Digests of the contacts stores entries may be used to make the comparison. Communication may be directly between the devices, such as by using Bluetooth, or may be via a network operator. The respective contacts stores may be held on the devices or by the network operator. The network operator may be used to make the comparison of store entries.