1.4: Pseudocode

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Overview

Pseudocode is an informal high-level description of the operating principle of a computer program or other algorithm.^[1]

Discussion

Pseudocode is one method of designing or planning a program. Pseudo means false, thus pseudocode means false code. A better translation would be the word fake or imitation. Pseudocode is fake (not the real thing). It looks like (imitates) real code but it is NOT real code. It uses English statements to describe what a program is to accomplish. It is fake because no compiler exists that will translate the pseudocode to any machine language. Pseudocode is used for documenting the program or module design (also known as the algorithm).

The following outline of a simple program illustrates pseudocode. We want to be able to enter the ages of two people and have the computer calculate their average age and display the answer.

Outline using Pseudocode

Input
    display a message asking the user to enter the first age
    get the first age from the keyboard
    display a message asking the user to enter the second age
    get the second age from the keyboard

Processing
    calculate the answer by adding the two ages together and dividing by two

Output
    display the answer on the screen
    pause so the user can see the answer

After developing the program design, we use the pseudocode to write code in a language (like C++, Java, Python, etc.) where you must follow the rules of the language (syntax) in order to code the logic or algorithm presented in the pseudocode. Pseudocode usually does not include other items produced during programming design such as identifier lists for variables or test data.

There are other methods for planning and documenting the logic for a program. One method is HIPO. It stands for Hierarchy plus Input Process Output and was developed by IBM in the 1960s. It involved using a hierarchy (or structure) chart to show the relationship of the sub-routines (or functions) in a program. Each sub-routine had an IPO piece. Since the above problem/task was simple, we did not need to use multiple sub-routines, thus we did not produce a hierarchy chart. We did incorporate the IPO part of the concept for the pseudocode outline.

Key Terms

pseudo: Means false and includes the concepts of fake or imitation.

References

cnx.org: Programming Fundamentals – A Modular Structured Approach using C++

Wikipedia: Pseudocode ↵