Older CPUs and some fairly modern microcontrollers are not made to readily support C compilers. Among those are the 1802, some 8-bit PICs, and the 6502 at the heart of the Commodore 64.

Computer RAM, where your variable data gets stored, is a bit like the cubbyholes in a kindergarten, only each box has an address instead of a nametag. When you use variables in C, the compiler ...