Online Coding Lessons Cheat Sheet 2026

The 30 highest-yield Online Coding Lessons facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which method is used to add an item to the end of a Python list? → .append()
2. In C, what does the sizeof operator return for an int on most modern 64-bit systems? → 4 bytes
3. What is a common reason your JavaScript code might not work? → A typo or missing bracket
4. Which clause in SQL is used to filter groups after a GROUP BY, similar to how WHERE filters rows? → HAVING
5. What does 'FPS' stand for in game development? → Frames Per Second
6. What is the purpose of the GROUP BY clause in SQL? → Groups rows sharing the same value for use with aggregate functions
7. What is a 'loop' used for in Scratch? → To repeat a set of blocks multiple times
8. What does 'NPC' stand for in game development? → Non-Player Character
9. Which HTML tag is used to define an unordered (bulleted) list? →
10. What is the purpose of the 'Pen' blocks in Scratch? → To draw lines and shapes on the stage with the sprite
11. How do sprites communicate with each other in Scratch? → Using the 'broadcast' and 'when I receive' blocks
12. In C++, which header provides std::cout and std::cin? →
13. In Scratch, what does the 'change x by' block do? → Moves the sprite horizontally
14. Which popular game engine uses C# as its primary scripting language? → Unity
15. Which SQL command is used to remove rows from a table? → DELETE
16. What is the worst-case time complexity of Bubble Sort? → O(n²)
17. What is the first index number of any array in JavaScript? → 0
18. What is the correct JavaScript syntax for modifying the HTML element below? → document.getElementById("demo").innerHTML = "Hello World!";
19. What does SQL stand for? → Structured Query Language
20. What is React Native? → A cross-platform framework for building mobile apps using JavaScript
21. Which sorting algorithm works by repeatedly swapping adjacent elements if they are in the wrong order? → Bubble Sort
22. What is a dangling pointer in C? → A pointer to freed or out-of-scope memory
23. What does 'in-app purchase' mean? → A transaction made within an app to unlock features or content
24. What is the correct format specifier to print a floating-point double with printf in C? → %f
25. In SQL, what does the wildcard character % represent when used with the LIKE operator? → Any sequence of zero or more characters
26. What does UI stand for in mobile app development? → User Interface
27. What type of JOIN returns only the rows that have matching values in both tables? → INNER JOIN
28. What is the Boolean value of an empty string in Python? → False
29. In C++, what does the 'virtual' keyword enable for a base class function? → Runtime polymorphism via dynamic dispatch
30. What is the correct CSS syntax to make all elements bold? → p {font-weight: bold}