What is debugging? | Year 3 Computing PDF Download

What is a computer bug?

• A mistake or error in an algorithm or computer program is referred to as a bug.
• We identify bugs when our computer programs fail to perform as anticipated.
• These issues can range from simple typing errors in the program code to more significant problems in the sequencing or order of instructions.
• Sometimes, bugs stem from errors made during the initial organization of instructions into an algorithm.
• When bugs are discovered, we undertake the process of correcting them, which is known as debugging. This involves identifying and fixing the errors in the program to ensure it operates correctly.

Checking for bugs as we go

Debugging is a crucial aspect of creating effective algorithms or computer programs. It is most effective when bugs are identified and resolved incrementally throughout the development process rather than being left until the end.
Let's consider a simple analogy, such as crafting directions for a friend to reach the science museum:

• Tell your friend the name of the museum and its location.
• Locate their address on a map.
• Determine the most efficient route from their residence to the science museum.
• Document these instructions for your friend to share with their parent or guardian.

Much like in programming, errors can occur at any stage of this process. For instance:

• Incorrectly typing the name of the museum.
• Using an outdated address, causing your friend to start in the wrong place.
• Selecting a path altered by a new construction site.
• Making a spelling error in the message you send them.

Any mistake in these steps could lead to your friend becoming disoriented, underscoring the importance of meticulous scrutiny at each phase. 

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Bugs in a computer program

• Introduction to Debugging: Debugging is the process of finding and fixing errors, or bugs, in a computer program. When a program does not work as expected, it likely contains bugs that need to be identified and corrected.
• Identifying Bugs: When creating a computer program, the desired outcome is known. If the program does not produce the expected result or stops working, it indicates the presence of bugs.
• Importance of Thorough Checking: Even with careful checking during the development process, some bugs might still persist in the final program. It is crucial to systematically check for and eliminate these bugs.
• Debugging Example - Hungry Alien Game: In the game "Hungry Alien," players control an alien character using arrow keys to collect food on the screen. However, after sharing the game with friends, reports came in that the game was not functioning properly.
  
• Debugging Process: When debugging a program like the Hungry Alien game, steps such as reviewing the code, testing different scenarios, and identifying specific issues are essential.
  

Finding the bug

• To begin debugging, it's crucial to recall what you expect to happen when the program runs, such as wanting the alien to move when the arrow keys are pressed.
• In the game, if the alien character did not respond to the arrow keys being pressed, the logical starting point for debugging would be to examine the section of the code that governs the movement of the alien character. 
• This involves checking how the arrow key inputs are detected and processed within the program, ensuring that the instructions for moving the alien are correctly implemented and responsive to user input.

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Persevering

• Debugging is crucial for learning how to write algorithms and computer programs.
• It's important to verify our algorithms and programs continuously, not just at the end.
• We should keep testing and checking until our program works as intended and solves the initial task or problem.

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Are bugs always bad?

• Making mistakes, identifying them, and correcting them is essential for everyone's learning process.
• Debugging our algorithms and programs is beneficial as it involves trying new ideas and challenging ourselves.
• Bugs are inevitable. Finding and fixing them improves our skills in writing computer programs.