What is a combinational circuit and give examples?

A combinational circuit is a digital circuit whose output depends only on the current inputs, with no memory or feedback. The same input combination always produces the same output. Examples include: Adders (half adder, full adder, ripple carry adder), Subtractors, Multiplexers (select one of many inputs), Demultiplexers (route input to one of many outputs), Encoders, Decoders, Comparators, and Arithmetic Logic Units (ALU). Design uses Boolean expressions or truth tables.