1 Data registers can hold numeric values such as integer and, in some architectures, floating-point values, as well as characters, small bit arrays and other data. 2  In some older and low end CPUs, a special data register, known as the accumulator, is used implicitly for many operations.
A commander-in-chief is the person or body that exercises supreme operational command and control of a nation's military forces or significant elements of those forces. In the latter case, the force element is those forces within a particular region, or associated by function.
The President of the USA is the Commander in Chief of the American Armed Forces. By deliberate design, that position can only be held by a civilian. It reinforces the concept that the military is subordinate to the rule of law as created by civilians in the form of the elected government.