Study

Questions I missed, things I need to pay attention to, study, or otherwise practice.

2020

Compound Assignment Operators

int x = 12;
int x += 2.6;

Compound assignment operators

Octal Literals

Octal Literals are defined by a zero prefix.

012 + 021 = ?
012 = 8 + 2 = 10
021 = 16 + 1 = 17
10 + 17 = 27

Decimal literals are defined in traditional form, 0-9 in base 10.

Hexadecimal literals are defined with the case insensitive character set a-fA-F0-9 and prefixed with 0x or 0X.

0xFace = 61440 + 2560 + 192 + 14 = 64206

Binary literals are defined with a 0b or 0B prefix.

0b10101 = 16 + 4 + 1 = 21

Return Types

Check return type of methods!

Binary Search Trees

Become familiar with how Binay Search Trees are created, and how one can manipulate them to create and level of elements.

More specifically, how many levels can a 32 element tree have if maximized?

Additionally, study Min Heap, Max Heap, Complete Trees, Perfect Trees, Strict Trees, Balanced Trees, BST Trees, and what a Child Node and Leaf Node is.

Min Heap
- Every node's child nodes are greater or equal to itself (i.e. smaller nodes higher up).
- Binary Tree is complete.
Max Heap
- Every node's child nodes are less than or equal to itself (i.e. greater nodes higher up).
- Binary Tree is complete.
Complete Trees *
Perfect Trees
Strict Trees
Balanced Trees
BST Trees
Child Node
Leaf Node

String.split Trailing Strings

String.split will create empty strings, but trailing empty strings will not be included in the final array. Additionally, a integer can be appended to define a limit to the number of "splits" that will occur.

out.println("xxOOxx".split("x"));
> ["", "", "00"]
out.println("xxx".split("x"));
> ["", "", ""]
out.println("xx0x0x0x".split("x"));
> ["", "", "0", "0", "0"]
out.println("xx0x0x0x".split("x", 3));
> ["", "", "0", "0x0x"]

Java's Primary Four OOP Concepts

Abstraction
- Complex objects are given relatively simple forms. Complex code is hidden within a much simpler face. Code is rewritten less.
Encapsulation
- Fields are kept private. Getters and Setters are used to access values within objects.
Inheritance
- Classes can use features and attributes from previously defined classes so as to not repeat code, and add customized implementations of code.

Polymorphism

Includes Method Overloading and Overriding
Method Overloading
- A method may perform differently based on how it is called (i.e. different return type given different arguments).
```
int calculate(int val)
double calculate(int val)
double calculate(int val, int limit)
```

Method Overriding

Uses Polymorphism to override the functionality of a parent class's methods.

class Person {
    void live() {e}
    void tick() {
        this.live()
    }
}

class Student extends Person {
    void study() {}
    void tick() {
        this.study()
        super.tick(); // Calls Person.tick()
    }
}

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