Algorithms- Pseudo Code

Understanding Pseudocode

Pseudocode is a way of expressing an algorithm in a structured but human-readable format.
Pseudocode is not a formal programming language, it uses English language and syntactical conventions from programming.
The main aim of pseudocode is clarity. It allows you to comment the general idea of a algorithim before coding it in a specific language.
In pseudocode, you may use programming constructs like loops (FOR, WHILE), conditions (IF, ELSE), input/output statements and arrays.

Writing Pseudocode

Start by defining the problem, and then decompose it into smaller tasks.
Each task can be defined as a sequence, a decision, or an iteration.
A sequence is a simple task that is performed and then the flow of control moves on.
A decision introduces a question: if the answer is ‘yes’, one action is performed; if ‘no’, another is done.
An iteration repeats an action until a condition is met.
Use identifiers (names) to refer to data that can be changed, such as variables or arrays.

Examples of Pseudocode

Here’s an example of a simple pseudocode to find the larger of two numbers:

  INPUT number_1, number_2
  IF number_1 > number_2 THEN
      OUTPUT number_1
  ELSE
      OUTPUT number_2
  ENDIF

The above pseudocode accepts two inputs, checks which is larger and outputs the larger number.

Evaluating and Improving Pseudocode

Pseudocode should be reviewed and refined for simplicity, clarity and efficiency.
Check for any logical errors or ambiguities; make sure the pseudocode does what it’s intended to do.
A common way of following through pseudocode is by dry running, which involves tracing through it step by step, tracking variable values to ensure logic works as intended.
Flowcharts can also be helpful to visualise the flow of control through the pseudocode.

Adapting Pseudocode to Coding

Once pseudocode is refined, use it to guide the development of your program in the specific language you are using.
Different languages may need different constructs, but pseudocode establishes the fundamental logic of the solution.
Remember that pseudocode isn’t strict; it is a tool for understanding and developing solutions, not the final code itself.