26.03.2024
02.04.2024

1. Properties: setters and getters
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/notes_4.html/

OOP_inherit.txt
... 2.2 Extend class Animal for properties: a) age: not negative integer number; minimal/default value = 0 , b) weight: positive float 

Proc properties?
- encapsulation (nesahej mi na me ... get of my cloud ... rolling stones); security view: control check 
- odvozeni veliciny (dry code) napr. vime velikost pole _n a z ni odvodime isEmpty, a nemusim si pamatoval dve hodnoty, 
coz zvysuje komplexitu a muze zpusobit inkonsistenci
- idea: "filtr pred vlozenim"



2. Pretezovani operatoru a indexery
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/notes_4.html/


DOPIMPLEMETOVAT
2.1 Polynomials
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/exercises_4.html

Design and implement a C# class Polynomial representing a polynomial of a single variable. Your class should include the following:

- a constructor that takes a variable number of arguments of type double, yielding a polynomial with those coefficients. 
For example: 
	new Polynomial(1.0, 4.0, 5.0)
	should yield the polynomial x2 + 4x + 5.

- a property degree that returns the degree of a polynomial. For example, the polynomial above has degree 2.
- an overloaded operator + that adds two polynomials
- an overloaded operator - that subtracts two polynomials
- an overloaded operator * that multiplies two polynomials, or a polynomial and a scalar
- a method that evaluates a polynomial for a given value of x
- a method that returns the first derivative of a polynomial
- a method asString() that yields a string such as "x^2 + 4x + 5"
- a static method Parse() that parses a string such as "x^2 + 4x + 5", yielding a polynomial.
- a indexer to change polynom 

- method Equals()
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/notes_6.html/
public override bool Equals(object? o) =>
        o is Point p && x == p.x && y == p.y;

The C# standard library contains a generic interface IComparable<T> that is implemented by all ordered built-in types. IComparable<T> means "comparable with objects of type T". For example, the built-in type int implements IComparable<int>, since integers are comparable with integers. IComparable<T> is defined like this:

interface IComparable<T> {

    int CompareTo (T other);

}

The CompareTo() method returns
    - a negative number if this object is less than other
    - 0 if this object equals other
    - a positive number if this object is greater than other

- rozsirte tridu Polynomial o komparator porovnavajici na zaklade stupne polynomu 



3. File / std IO
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/notes_3.html/
- StreamReader, StreamWriter from System.IO namespace 
- reading all lines:
	while (Console.ReadLine() is string line) {
    		... do something with line ...
	}
- closing files with 'using': 
	using (StreamWriter sr = new StreamWriter(filename)) {
    		... use sr here ...
	}

3.3 Příklad wc: napište obdobu Unix utility wc počítající počet: a) řádků "-l", b) slov "-w", c) písmen "-c", 
(nedelat: d) není li zadán parametr výpisu, jen jmeno souboru, vytiskne vše)
v souboru dle zadaného parametru, obé (parametr, co počítáme i název souboru) zadané z příkazové řádky 
https://cs.wikipedia.org/wiki/Wc_(Unix)
https://www.geeksforgeeks.org/wc-command-linux-examples/

    -l <soubor>  : vytiskne počet řádek
    -c <soubor>  : vytiskne počet bytů
    -m <soubor>  : vytiskne počet znaků
    -L <soubor>  : vytiskne délku nejdelší řádky
    -w <soubor>  : vytiskne počet slov

Příklad: wc -l "to_nechces_cist.txt" 


4. Generika
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/notes_6.html/

4.2 Implementujte generický Stack<T>
- push, pop, isEmpty, size 
- konstruktor pro zadanou maximalni velikost
- vyuzit property?

5. Interface
https://ksvi.mff.cuni.cz/~dingle/2023-4/prog_2/notes_5.html/
Navrhnete a implementujte interface IStack pro Stack a vytvorte tridu ArrayStack implementujici interface IStack

5.1 Generic interfaces

An interface may also be generic. For example, here's a generic interface IStack<T>, which is a stack of elements of type T:

	interface IStack<T> {
	    bool isEmpty { get; }
	    void push(T i);
	    T pop();
	}


6. The C# standard library contains a generic interface IComparable<T> that is implemented by all ordered built-in types. IComparable<T> means "comparable with objects of type T". For example, the built-in type int implements IComparable<int>, since integers are comparable with integers. IComparable<T> is defined like this:

interface IComparable<T> {

    int CompareTo (T other);

}

The CompareTo() method returns
    - a negative number if this object is less than other
    - 0 if this object equals other
    - a positive number if this object is greater than other

Rozsirte tridu Animals o komparator porovnavajici na zaklade veku zvirete


8. C# collection classes