IT 145 Guide to Pseudocode Pseudocode
IT 145 Guide to Pseudocode Pseudocode is an intermediary step between reading a problem statement and writing the code to solve the problem. It serves as a blueprint for your program to guide you through, just like contractors start with a blueprint before building a house. Use your pseudocode as a tool to begin thinking about your program, but keep in mind it might not be the final solution to the problem. Pseudocode is written in a natural language using some programming keywords. Consider the first example below: INCREMENT the number of apples in the basket by one Notice in the example that it fully describes, in natural language, what needs to be done in the program. When writing pseudocode, start at the beginning of what you need the program to do. Then work through, step by step, until reaching the end of what’s required by the program in the problem statement. This is putting the problem in sequence. For example, making a peanut butter sandwich: OBTAIN a plate OBTAIN two slices of bread OBTAIN a jar of peanut butter OBTAIN a knife Place the slices of bread on the plate Open the jar of peanut butter Spread peanut butter on one bread slice with the knife Place the empty slice of bread on top of the slice with peanut butter Serve There are several common keywords that get capitalized as they refer to actions taken in the program. Those words include READ, WRITE, PRINT, DISPLAY, CALCULATE, SET, INCREMENT, and more. You can also show choices and loops in pseudocode. Just like in coding, when an item is nested inside another item, you indent that line of pseudocode. Below are three generic examples: IF condition THEN Include the first sequence ELSE Include the second sequence ENDIF WHILE condition Include the sequence ENDWHILE FOR loop parameters Include the sequence ENDFOR You can also use the keyword CALL to reference another algorithm written separately. Now look at the following more complete examples of both good and bad pseudocode to get a general feel of how to write it. Bad Example (Vague and incomplete): function doProgrammingHomework(): Get things for homework Write the code correctly Finish the homework Bad Example (Too technical; does not follow natural language usage): function doProgrammingHomework(): getComputer(); openBlackboard(); for (var count = 0; count < problems.length(); count++) solve(); while (!compile) debug(); submit() shutDownComputer(); Good Example (Follows steps one at a time through the end of the algorithm): function doProgrammingHomework(): GET a computer OPEN the Blackboard module FOR each of the problems in the module Complete problem WHILE the problem does not compile Debug ENDWHILE Submit the assignment ENDFOR Shut down the computer Remember not to make your pseudocode too technical. You are not trying to write the code itself, just a plan as a stepping-stone after the initial problem to get your creative juices flowing.