In digital circuit theory, combinational logic (also called combinatorial logic) is a type of logic circuit whose output is a pure function of the present input only. Digital electronics are Electronics systems that use Digital signals Digital electronics are representations of Boolean algebra also see In Computer programming, a function may be described as pure if both these statements about the function hold The function always evaluates the same This is in contrast to sequential logic, in which the output depends not only on the present input but also on the history of the input. In Digital circuit theory sequential logic is a type of logic circuit whose output depends not only on the present input but also on the history of the input

In other words, sequential logic has memory while combinational logic does not. Computer data storage, often called storage or memory, refers to Computer components devices and recording media that retain digital

Combinational logic is used in computer circuits to do Boolean algebra on input signals and on stored data. A computer is a Machine that manipulates data according to a list of instructions. Boolean algebra (or Boolean logic) is a logical calculus of truth values, developed by George Boole in the late 1830s Practical computer circuits normally contain a mixture of combinational and sequential logic. For example, the part of an arithmetic logic unit, or ALU, that does mathematical calculations is constructed in accord with combinational logic, although the ALU is controlled by a sequencer that is constructed in accord with sequential logic. In Computing, an arithmetic logic unit ( ALU) is a Digital circuit that performs Arithmetic and Logical operations