What are registers in central processing unit?

What are the three major components of the central processing unit?

The central processing unit has two parts: the arithmetic logic unit and the control unit.In some architectures the arithmetic logic unit may contain a small local memory for operands/results (e.g. accumulator, floating point registers, general purpose registers), but not all do.In some architectures or implementations the control unit may contain a read only memory for the microcode that interprets instructions, but not all do.In almost all modern microprocessors a cache memory is attached to the central processing unit, as placing it in very close proximity to the central processing unit significantly increases performance, but cache memory is really part of the memory unit not the central processing unit.