What is the function of a computer?

While the uses and applications of computers and computer-based technology are nearly endless, the core functions of computers can be placed into four main categories. All of the categories revolve around some aspect of data.
Input—A computer receives and accepts data that is input by a user. More often than not, that is done with a keyboard and mouse, but it could also be done with webcams, other computers, and various data storage devices.  
Storage—A computer can store vast amounts of data in multiple formats.
Processing—This is probably one of the most important functions of a computer. Computers can take input data and process it to give a user the desired information or organization of that information.  
Output—This is the computer's ability to display processed information to a user. A computer can output information through its monitor, speakers, and/ or printer.