Byte Order
There are two ways that integers can be stored in a computer.
One corresponds to number the bytes within a word with the lowest number in
the leftmost position. Naturally, the other one corresponds to numbering the
bytes within a word with the lowest number in the rightmost position.
They are named big-endian and little-endian respectively.
In a byte, big Endian Representation: A, A+1, A+2, A+3
Ina byte, Little Endian Representation: A+3, A+2, A+1 , A
Byteorder testing program is here.