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KaiquanMah
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TurkuBasicOOPinJava
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TurkuBasicOOPinJava
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Week 3: Objects, files and exceptions
71.8 kB
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38 commits
KaiquanMah
System.out.println("<menu item i>");
37afcbe
verified
5 months ago
10. Array from list
Safe
2.2 kB
Create 10. Array from list
5 months ago
11a Hashmap
Safe
3.07 kB
HashMap<String, Integer>; put get containsKey keySet(=k ONLY)
5 months ago
11b. Combine names and grades
Safe
2.21 kB
HashMap<String, Integer> map = new HashMap<>();
5 months ago
12. Coldest city
Safe
2.68 kB
for (String city : cityNTemps.keySet())
5 months ago
13a. Using existing libraries
Safe
537 Bytes
Random.nextInt(upToButNotIncl)
5 months ago
13b. Draw lottery numbers
Safe
2.74 kB
r.nextInt(39)
5 months ago
14a Class StringBuilder
Safe
1.96 kB
StringBuilder str = new StringBuilder("<urStr>");
5 months ago
14b Starsquare
Safe
1.61 kB
Create 14b Starsquare
5 months ago
15a Math-library
Safe
558 Bytes
Math.PI; Math.pow
5 months ago
15b. Math-class methods
Safe
378 Bytes
abs exp log floor max signum negateExact
5 months ago
16a Files and exceptions
Safe
876 Bytes
Create 16a Files and exceptions
5 months ago
16b. Players from FILE
Safe
2.07 kB
Scanner reader = new Scanner(new File("fileName.txt")); list.add(reader.nextLine());
5 months ago
17a Handling file contents
Safe
2.27 kB
String row = reader.nextLine(); String[] chunks = row.split(","); Integer.valueOf(chunk);
5 months ago
17b. Read numbers from a file
Safe
2.36 kB
Create 17b. Read numbers from a file
5 months ago
18a 3 Types Exceptions, TRY-CATCH, throws FileNotFoundException
Safe
3.58 kB
Create 18a 3 Types Exceptions, TRY-CATCH, throws FileNotFoundException
5 months ago
18b. Add numbers to list 2
Safe
2.05 kB
Create 18b. Add numbers to list 2
5 months ago
19. Phone book 1: Adding a number
Safe
2.17 kB
public static void addNumber(HashMap<String,String> numbers)
5 months ago
1a Objects and references
Safe
3.46 kB
obj1.equals(obj2)
5 months ago
1b. Calculator
Safe
2.14 kB
Create 1b. Calculator
5 months ago
2. Names to list - equals
Safe
2.05 kB
equals
5 months ago
20. Phone book 2: Searching for a number
Safe
1.77 kB
containsKey get
5 months ago
21. Phone book 3: Listing numbers - Extract HASHMAP KEYS, then SORT
Safe
2.59 kB
String[] arrKeys = numbers.keySet().toArray(new String[0]); Arrays.sort(arrKeys);
5 months ago
22. Phone book 4: Menu
Safe
3.33 kB
System.out.println("<menu item i>");
5 months ago
3a. Objects as parameters and return values
Safe
679 Bytes
someMethod(ArrayList<Integer> list)
5 months ago
3b. Add sum to list - RECREATE LIST
Safe
2.15 kB
ArrayList<Integer> lista = new ArrayList<>(); for (int l : pa) lista.add(l);
5 months ago
4. Remove negative numbers - get, remove
Safe
2.49 kB
get, remove
5 months ago
5a. Method side effects
Safe
1.11 kB
eg change order
5 months ago
5b. Second smallest without side effects
Safe
2.2 kB
Collections.min/max, THEN go through list to find secondSmallest
5 months ago
6B. Create a list
Safe
2.04 kB
Create 6B. Create a list
5 months ago
6a. Objects as return values
Safe
1.8 kB
ArrayList<String> list = new ArrayList<>();
5 months ago
7. Convert to a number list
Safe
3.06 kB
"" + someInt; Integer.parseInt(str)
5 months ago
8. Combine lists
Safe
2.99 kB
newList.addAll(list1); Collections.sort(newList)
5 months ago
9a. Data structure - ARRAY
Safe
3.36 kB
String[] names = new String[16]; arr.length; list.size(); str.length();
5 months ago
9b. Sum of array elements
Safe
1.28 kB
Create 9b. Sum of array elements
5 months ago