What is an algorithm Explain the criteria or properties to be satisfied by algorithm

1] What is an algorithm Explain the criteria or properties to be satisfied by algorithm

An algorithm is a finite set of instructions to solve a particular problem. In addition, all algorithms must satisfy the following criteria:

1. Input. Zero or more quantities are externally supplied.
2. Output. At least one quantity is produced.
3. Definiteness. Each instruction is clear and unambiguous. It must be perfectly clear what should be done.
4. Finiteness. If we trace out the instruction of an algorithm, then for all cases, the algorithm terminates after a finite number of steps.
5. Effectiveness. Every instruction must be very basic so that it can be carried out, in principle, by a person using only pencil and paper. It is not enough that each operation be definite as in criterion c; it also must be feasible.