Debugging | Year 5 Computing PDF Download

What is debugging?

• Debugging is a crucial process in algorithm development and computer programming.
• It entails testing the results of programs and identifying any errors or mistakes, which could be in the original algorithms or the final program code.

Different types of bugs

Syntax Bugs

• A syntax bug arises from typing mistakes and errors in the symbols, letters, and numbers used in the code.
• These errors make the code incomprehensible to the computer, often preventing the program from running at all.
• For instance, a missing semicolon in a line of code can lead to a syntax bug.

Logic Bugs

• Logic bugs occur due to errors in the organization or sequence of the algorithm or program instructions.
• These bugs can result from using the wrong command, omitting a necessary step, or arranging instructions incorrectly.
• Unlike syntax bugs, programs with logic bugs can still run but may produce unexpected or erroneous outcomes.
• For example, a logic bug in a sorting algorithm might cause the program to sort data incorrectly.

Where are the bugs hiding?

When we engage in the process of creating a computer program, it is crucial to acknowledge the various stages involved. This comprehensive understanding aids us in refining our debugging skills and enhancing the quality of our algorithms and programs.

• We commence by breaking down the task or problem into smaller, manageable sections through a process known as decomposition.
• Subsequently, we formulate a set of rules and instructions for the different components of the task or problem, which are referred to as algorithms.
• Lastly, we translate these algorithms into a format that a computer can interpret, known as code.

Throughout these stages, errors or bugs, which are inaccuracies in a computer program impacting the output, can manifest. It is imperative to scrutinize each phase meticulously during the debugging process. 

The debugging and testing cycle

• One crucial strategy for successful programming is to engage in testing and debugging throughout all stages of a project, rather than leaving it all until the end.
• By continuously testing and debugging as we progress, we save time that would otherwise be spent combing through extensive lines of code at the project's completion.
• Ensuring that our program functions as intended is essential. By testing and debugging iteratively, we can promptly identify and rectify any issues that arise.
• The iterative cycle of testing, debugging, and retesting is a fundamental skill for aspiring programmers to master.

Teamwork can defeat the bugs

• Problem-solving and debugging are often easier when you have friends to assist you, just like in any collaborative effort.
• Another person might spot a bug that you missed, and vice versa, enhancing the effectiveness of debugging.
• Working effectively as part of a team is a valuable skill for successful debugging. In complex projects, computer programmers frequently collaborate in teams to debug issues.
• You can practice this skill with classmates, friends, and family as you learn to write your own computer programs.

Debugging in real life

• When new features and characters are released for computer games, many of us eagerly download them right away.
• However, the initial version of these updates often contains a few bugs that were missed during the testing phase.
• These bugs can cause issues such as incorrect game controls, graphic glitches, and characters behaving oddly.
• Programmers gather feedback on these bugs and then proceed to debug the programs. They release an updated version, typically labeled with a version number like 1.2, to address these issues.

The 18 million dollar bug

• The story of the Mariner 1 spacecraft in 1962 is a stark example of how a small bug can lead to significant consequences.
• This unmanned spacecraft was designed to travel nearly 200 million miles to Venus and transmit valuable data to Earth's scientists.
• However, an error occurred when someone mistakenly inputted the wrong symbol into the program's code, which went unnoticed.
• As a result, Mariner 1 veered off its intended trajectory shortly after launch, prompting its destruction just 290 seconds into flight to prevent a potential collision with Earth.