What is the core difference between algorithm and pseudocode?

Question

As the question describe itself "What is the core difference between algorithm and pseudocode?".

Answer 1

I think all the other answers give useful explanations and definitions, but I'm going to give mine.

An algorithm is the idea of how to obtain some result from some input. It is an abstract concept; an algorithm is not something material by itself, but more something like an imagination or a deduction, a thing that only exists in the mind. In the broad sense, any sequence of steps that give you some thing(s) from other thing(s) could be called an algorithm. For example, if the screen of your computer is dirty, "spraying some glass cleaner on it and wipe it with a cloth" could be said to be an algorithm to solve the problem of how to obtain a clean screen form a dirty screen. It is important to note the difference between the problem itself (getting a clean screen) and the algorithm (wiping it with a cloth and cleaner); generally, several different algorithms are possible to solve the same problem. The idea of complexity is inherent to the algorithms itself, not the problem or the particular implementation or execution of the algorithm.

Pseudocode is a language to express algorithms. Since, as said before, algorithms are only concepts, we need to use something to express them and explain them to other people. Pseudocode is a convenient way for many computer science algorithms, because it is usually unambiguous, easy to read and somewhat similar to many programming languages. However, a specific programming language like C or Java can also be used to express and algorithm (it's just less convenient to those not familiarized with that language). In other cases, pseudocode may not be the best way to express an algorithm; for example, many graph and tree algorithms can be explained more easily with drawings or diagrams. In the previous example, the algorithm to get your screen cleaned is probably better expressed in a natural language like English, because it is simple and specific enough for that case.

Obviously, terms are frequently used loosely and exchanged depending on the context, and there's no need to be nitpicky about it, but I think it is important to have the difference clear. An algorithm doesn't stop being an algorithm just because it is written in Python instead of pseudocode. Pseudocode is just a convenient and widespread communication tool to express them.

Answer 2

algorithm

An algorithm is a procedure for solving a problem in terms of the actions to be executed and the order in which those actions are to be executed. An algorithm is merely the sequence of steps taken to solve a problem. The steps are normally "sequence," "selection, " "iteration," and a case-type statement.

Pseudocode

Pseudocode is an artificial and informal language that helps programmers develop algorithms. Pseudocode is a "text-based" detail (algorithmic) design tool.

The rules of Pseudocode are reasonably straightforward. All statements showing "dependency" are to be indented. These include while, do, for, if, switch. Examples below will illustrate this notion.

Answer 3

From Wikipedia :

Starting from an initial state and initial input (perhaps empty), the instructions describe a computation that, when executed, proceeds through a finite number of well-defined successive states, eventually producing "output" and terminating at a final ending state. 

With a pseudo language one can implement an algorithm without using a programming language such as C.

An example of pseudo language is Flow Charts.

Answer 4

An algorithm is something (a sequence of steps) you can do. Pseudocode is a notation to describe an algorithm.

Answer 5

Algorithm is something which is represented in mathematical terms. It includes, analysis, complexity considerations(best, average and worstcase analysis etc.).Pseudo code is a human readable representation of a program.