This is one of four videos on thinking procedurally. In this video we discuss the importance of identifying the components of a problem. Hypothetically speaking it's easy for a single programmer to produce a solution for a trivial problem. However most real world problems are more complex.
Imagine asking one person to solve a problem. person to write the software for a modern smartphone. This problem is far from trivial. Modern phones use complex operating systems.
They're essentially handheld computers capable of running other programs. Clearly, a single programmer cannot tackle this problem alone. One of the key aspects of thinking procedurally is identifying the individual parts of a bigger problem.
In this way, a large, complex task can be broken down and tackled in smaller, more manageable chunks. The first step an analyst needs to undertake is identifying the components of the problem. A common approach to solving a large problem is to break it down into a top-down modular design or structure diagram.
using a method called stepwise refinement. Using top-down design, the task the program needs to perform is split into smaller subtasks. Each of these subtasks can be split up into even smaller subtasks if necessary. The aim is to end up with subtasks that perform a single functional task that can be tackled as small, largely independent modules.
The lowest level of subtasks can be assigned to individual programmers or small teams. They can be written and tested in isolation before being integrated into the overall solution. Here's an example of a structure diagram created for a program that calculates wages.
The top layer features several parts. A section to get the ploy's details, calculate the gross pay, calculate deductions, calculate the net pay, and finally to output a wage slip. Two of the subtasks are broken down into further subtasks.
For example, calculate gross pay is the result of two separate actions, calculating the normal wages and also calculating over time. In a similar way, calculate deductions is made up from first calculating any tax and then calculating any national insurance. Having watched this video, you should be able to answer the following key question.
How can we use top-down modular design to produce a structure diagram and why are they useful? To help get your head around everything to do with computational thinking, we have a freely available downloadable cheat sheet. It's got two sides to it.
There's a basic poster that reminds you at a top level what the five different strands are, and on the back there's a much more detailed explanation. This resource is completely free from student.craiganddave.org. Just scroll down and select the section that says A-Level Revision. You'll then see a section called OCR, AS and A-Level and there's a number of cheat sheets in there, including two versions of the computational one.
Just click download to get the zip file.