Java, before term starts

The pre-term course, its exercises and its projects, with a real Java compiler in your browser. Nothing to install, no account to create.

Not sure where to start? The chapter Find your level: 19 questions, about fifteen minutes, and for each topic the chapter to reread and the exercises to do.

1. You write Java in the editor, spread over as many files as needed: one public class per file, as in a real project.
2. Run compiles your code with the Eclipse compiler, then runs it on a Java virtual machine that lives entirely in the tab. The errors shown are those of a real compiler.
3. Check runs tests written in Java on your methods and tells you, case by case, what was expected and what your code returned.
4. Your code is kept in this browser: you can close the tab and pick up later.

Lecture notes

1. Find your level : 19 questions, about fifteen minutes, to find out which chapters to reread and which exercises to do first.
2. Language overview : What Java is, what a source file is, and the rules that are not up for debate.
3. Variables and identifiers : A variable is a named, typed box that points to a memory cell.
4. Data types : The eight primitive types, their size, their limits, and conversions.
5. Basic semantics : Instructions, assignment, variable scope and operators.
6. Control structures : if, the ternary operator, switch, while, do…while and for.
7. Standard input and output : stdout, stderr, stdin, print/println and the Scanner.
8. Functions : Declaration, prototype, return, overloading and variadic arguments.
9. Splitting and organising code : Packages and the program's entry point.
10. Arrays : Declaration, length, indices and arrays of arrays.
11. Strings : String is an object, not a primitive type, and that changes everything.

Sequences

1. Printing an age
2. Declaring several types
3. Why int x = 10.5 is rejected
4. Positive, negative or zero
5. Even or odd
6. Vowel or consonant (switch)
7. Even numbers from 0 to 20 (for)
8. Adding until past 100 (while)
9. From 1 to 10 (do…while)
10. Prime number
11. Factorial
12. Fibonacci sequence
13. Length of a string
14. Recursive sum
15. Sum of an array
16. Average of an array
17. Searching for a value
18. Is the array sorted?
19. 3×3 matrix
20. Counting a letter
21. Palindrome
22. Reversing the words of a sentence
23. == or equals?
24. Average of 5 integers typed in
25. Operations menu
26. Celsius to Fahrenheit
27. Password (do…while)
28. GCD (Euclid’s algorithm)
29. Fast exponentiation
30. Bubble sort
31. Insertion sort
32. Dot product
33. The Personne class
34. Encapsulation: getters and setters
35. Inheritance: the Etudiant class
36. Overriding toString()
37. Console calculator
38. Guess the number
39. Rock-paper-scissors
40. Mini address book
41. Hangman