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TurkuBasicOOPinJava / Week 3: Objects, files and exceptions

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System.out.println("<menu item i>");

37afcbe verified 5 months ago

10. Array from list

2.2 kB

Create 10. Array from list 5 months ago
11a Hashmap

3.07 kB

HashMap<String, Integer>; put get containsKey keySet(=k ONLY) 5 months ago
11b. Combine names and grades

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HashMap<String, Integer> map = new HashMap<>(); 5 months ago
12. Coldest city

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for (String city : cityNTemps.keySet()) 5 months ago
13a. Using existing libraries

537 Bytes

Random.nextInt(upToButNotIncl) 5 months ago
13b. Draw lottery numbers

2.74 kB

r.nextInt(39) 5 months ago
14a Class StringBuilder

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StringBuilder str = new StringBuilder("<urStr>"); 5 months ago
14b Starsquare

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Create 14b Starsquare 5 months ago
15a Math-library

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Math.PI; Math.pow 5 months ago
15b. Math-class methods

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abs exp log floor max signum negateExact 5 months ago
16a Files and exceptions

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Create 16a Files and exceptions 5 months ago
16b. Players from FILE

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Scanner reader = new Scanner(new File("fileName.txt")); list.add(reader.nextLine()); 5 months ago
17a Handling file contents

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String row = reader.nextLine(); String[] chunks = row.split(","); Integer.valueOf(chunk); 5 months ago
17b. Read numbers from a file

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Create 17b. Read numbers from a file 5 months ago
18a 3 Types Exceptions, TRY-CATCH, throws FileNotFoundException

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Create 18a 3 Types Exceptions, TRY-CATCH, throws FileNotFoundException 5 months ago
18b. Add numbers to list 2

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Create 18b. Add numbers to list 2 5 months ago
19. Phone book 1: Adding a number

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public static void addNumber(HashMap<String,String> numbers) 5 months ago
1a Objects and references

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obj1.equals(obj2) 5 months ago
1b. Calculator

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Create 1b. Calculator 5 months ago
2. Names to list - equals

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equals 5 months ago
20. Phone book 2: Searching for a number

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containsKey get 5 months ago
21. Phone book 3: Listing numbers - Extract HASHMAP KEYS, then SORT

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String[] arrKeys = numbers.keySet().toArray(new String[0]); Arrays.sort(arrKeys); 5 months ago
22. Phone book 4: Menu

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System.out.println("<menu item i>"); 5 months ago
3a. Objects as parameters and return values

679 Bytes

someMethod(ArrayList<Integer> list) 5 months ago
3b. Add sum to list - RECREATE LIST

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ArrayList<Integer> lista = new ArrayList<>(); for (int l : pa) lista.add(l); 5 months ago
4. Remove negative numbers - get, remove

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get, remove 5 months ago
5a. Method side effects

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eg change order 5 months ago
5b. Second smallest without side effects

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Collections.min/max, THEN go through list to find secondSmallest 5 months ago
6B. Create a list

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Create 6B. Create a list 5 months ago
6a. Objects as return values

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ArrayList<String> list = new ArrayList<>(); 5 months ago
7. Convert to a number list

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"" + someInt; Integer.parseInt(str) 5 months ago
8. Combine lists

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newList.addAll(list1); Collections.sort(newList) 5 months ago
9a. Data structure - ARRAY

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String[] names = new String[16]; arr.length; list.size(); str.length(); 5 months ago
9b. Sum of array elements

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Create 9b. Sum of array elements 5 months ago