Define a register, what is the function of a register? Name the important register of CPU?

Ans: A register is a temporary storage device which holds data (or an instruction) as long as its being manipulated(or being interpreted ) each register within the CPU performs a specific role. 

       Registers are used in many different ways in a computer. Depending on the particular use of a register, a register may hold data being processed, an instruction being executed, a memory or I/O address to be accessed, or even special binary codes used for some other purpose, such as codes that keep track of the status of the computer or the conditions of calculation may be used for conditional branch instruction some registers serve many different purposes, while others are designed to perform a single, specialized task. 

Name of the some important registers are as follows: 

1. Accumulator(AC)
2. Status Register
3. Memory Buffer Register(MBR)
4. Memory Address Register(MAR)
5. Instruction Register(IR)