Pseudocode is a way to represent algorithms or program logic using a mixture of natural language and simple programming constructs. It helps in planning and designing the structure of a program without worrying about the specific syntax of a programming language.

Most programs are developed using programming languages. These languages have specific syntax that must be used so that the program will run properly. Pseudocode is not a programming language😒, it is a simple way of describing a set of instructions that does not have to use specific syntax.

Pseudo Code Notation 🧩

There is no strict set of standard notations for pseudocode, but some of the most widely recognized are:

Write Pseudo Codes 📝

In pseudocode, it is customary to include a BEGIN keyword at the beginning to signify the start of the program, just as in a flowchart we use a "Start" terminal. Additionally, it is essential to include an END keyword at the end to indicate the conclusion of the program, similar to the "Stop" terminal in a flowchart.

• Declaring your variables:

  • SET : To indicate that the user will be setting a value or variable in pseudocode, you can use the SET keyword.

  SET name = "John"
  SET age = 25

  In pseudocode, when assigning a value to a variable, we typically use double quotation marks ("" or '') to indicate that the value is a word or a string. On the other hand, when the value is an integer or a numeric value, we simply use the number itself without any quotation marks.

• Using Input and Output in Pseudo Code:

  • INPUT : To indicate that the user will be inputting something in pseudocode, you can use the INPUT keyword.

    INPUT "Enter your name: " as name

    This example prompts the user to enter their name and stores the input in the variable name.

  • OUTPUT : To indicate that an output will appear on the screen in pseudocode, you can use the OUTPUT keyword.

    OUTPUT "Hello, Welcome to the program."

    This example outputs a greeting message.

• Use standard programming constructs: Pseudocode uses common programming constructs like loops, conditionals:

  • Selection: Checks a condition and performs an action based on the result.

    IF – THEN – ELSE : A decision in pseudocode, where a choice is made based on a condition, can be represented using the IF - THEN - ELSE structure.

    BEGIN
    	IF age >= 18 THEN
    	    OUTPUT "You are eligible to vote."
    	ELSE
    	    OUTPUT "Sorry, you are not eligible to vote yet."
    	END IF
    END

    This example checks if the variable age is greater than or equal to 18. If the condition is true, it outputs a message indicating eligibility to vote. Otherwise, it outputs a message stating that the person is not eligible to vote yet.

    Using the IF - THEN - ELSE structure allows you to create decision-making processes in pseudocode. It enables the program to choose between different paths of execution based on the evaluation of a condition.

    The keyword THEN is optional in some pseudocode conventions. So, it can be written as IF age >= 18 without explicitly using THEN.

    By using IF END, you ensure that all the statements within the conditional block are enclosed, making it clear which statements are executed based on the condition.

  • Looping: Executes a set of instructions repeatedly until a certain condition is met:

    WHILE – DO : A loop in pseudocode that has a condition at the beginning is commonly represented by the WHILE keyword.

    BEGIN
    	SET count = 0
    	WHILE count < 5 DO
    	    OUTPUT "Count: " + count
    	    SET count = count + 1
    	END WHILE
    END

    This example demonstrates a WHILE loop that continues iterating as long as the count variable is less than 5. It outputs the value of count on each iteration.

    Using the WHILE keyword helps to signify a loop that iterates based on a condition that is checked at the beginning of each iteration. It ensures that the loop will continue executing as long as the condition remains true.

    By using WHILE END, you can easily identify the beginning and end of the loop, ensuring that the loop's body is clearly defined and contained within the loop structure.

    FOR – TO – DO : A counting loop in pseudocode is commonly represented by the FOR keyword. It allows for a specific number of iterations based on a defined range or condition.

    BEGIN
    	FOR i = 1 TO 5 DO
    	    OUTPUT "Iteration: " + i
    	END FOR
    END

    This example uses a FOR loop to iterate from 1 to 5. It outputs a message indicating the current iteration number.

    By using the FOR - TO - DO structure, you establish a counting loop where the counter variable is automatically incremented or decremented with each iteration until a specific range or condition is met. The TO keyword represents the range of values that the loop will iterate over.

    By using FOR END, you establish a clear boundary for the iteration block, making it evident which statements are executed within the loop and helping to prevent errors in cases where additional code should not be part of the loop.

    REPEAT – UNTIL : A loop in pseudocode that has a condition at the end can be represented using the REPEAT UNTIL structure.

    BEGIN
    	SET number = 0
    	REPEAT
    	    INPUT "Enter a positive number: " as number
    	UNTIL number > 0
    END

    This example repeatedly prompts the user to enter a number until they input a positive number. The loop continues until the condition number > 0 is met.

    Using the REPEAT - UNTIL structure helps create a loop where the condition is evaluated at the end of each iteration. This ensures that the loop will execute at least once, as the condition is checked after the initial iteration.

General Rules ⚖️

📎 Always capitalize the initial word (often one of the main six constructs).

📎 Make only one statement per line.

📎 Indent to show hierarchy, improve readability, and show nested constructs.

📎 Always end multi-line sections using any of the END keywords (ENDIF, ENDWHILE, etc.).

📎 Keep your statements programming language independent.

📎 Keep it simple, concise and readable.