Explanation:
In the context of digital computers, a register is a temporary storage unit within the CPU (Central Processing Unit) that is used to hold data, instructions, or memory addresses during processing. It is an essential component of a computer's architecture and plays a crucial role in executing instructions and performing operations.

Functions of a Register:
Registers serve various purposes in a digital computer system, including:
1. Data Storage: Registers are used to store temporary data that is currently being processed by the CPU. This data can include operands, intermediate results, or values fetched from memory or other registers.
2. Instruction Execution: Registers hold the instructions that are being executed by the CPU. These instructions are fetched from memory and placed in the instruction register, where they are decoded and executed.
3. Address Storage: Registers can store memory addresses that are used for accessing data in primary or secondary storage. These addresses are used during memory operations such as reading or writing data.
4. Control Signals: Some registers store control signals that determine the operation of various components within the CPU. These signals can include flags, status bits, or control bits that enable or disable specific features or functionalities.

Types of Registers:
There are different types of registers present in a computer system, including:
1. General-Purpose Registers: These registers can be used for various purposes, such as storing data, addresses, or instructions. They are often used by the programmer to hold intermediate results or to perform arithmetic and logical operations.
2. Special-Purpose Registers: These registers have dedicated functions and are used for specific tasks. Examples include the program counter (PC), stack pointer (SP), and accumulator.
3. Control Registers: These registers store control information and are used to configure or control specific operations within the CPU. Examples include the status register, interrupt enable/disable register, and memory management unit registers.

Conclusion:
In conclusion, a register in a digital computer is a temporary storage unit within the CPU that is used for holding data, instructions, addresses, and control signals during processing. It is a crucial component of a computer's architecture and is utilized in various ways to facilitate efficient execution of instructions and operations.