word size on msdn
Variables are pretty crucial to any language, and C is no exception.Unlike other languages it’s quite important to understand how memory works to understand C variable types. So here’s a quick refresher. Memory on any computer is just a big list of numbers.Each number is called a byte and each byte has an address – a unique value that identifies it - usually counting up from 0.A byte is made from 8 binary digits (bits), and can hold 256 different values (2 to the power of 8 – 2 8 ).To store anything useful you usually need to group bytes together so that they can hold more information.For example, 2 bytes together can store 2 16 = 65536 different values.In every version of C you get the following different data types built in (all descriptions are for a standard PC program – other computers use different sizes):