What are the functional components of a digital computer ?

The functional components of a digital computer are as follows:

1. Input Unit — It is responsible for taking input for the computer. For example, keyboard.
2. Output Unit — It is responsible for giving output to the user. For example, monitor.
3. Central Processing Unit (CPU) — It is responsible for processing the data and instructions. It has the following sub-components:
   
   1. Arithmetic and Logic Unit (ALU)
   2. Control Unit (CU)
   3. Registers
4. Primary Memory — It is the internal volatile­ memory where data and instructions are stored during processing.
5. Secondary Storage Unit — It refers to the external storage devices which provide permanent memory to the computer system.