====== 7. Objekty ======

===== Komplexní čísla =====

<code python>
# definice tridy - popis entity
class Complex:

    # kontruktor
    def __init__ (self, r, i):

        self.re = r
        self.im = i
        self.print_format = "slozky"
    
    def print (self):

        print("{} {}".format(self.re, self.im))

    def __str__ (self):

        if self.print_format == "slozky":
            return "{0}{1:+}i".format(round(self.re,2), round(self.im, 2))
        else: 
            return "A*e^i(modul)"

    def add (self, other):

        self.re = self.re + other.re
        self.im = self.im + other.im

    def __add__ (self, other):

        return Complex(self.re + other.re, self.im + other.im)
       
    def modul (self):
        """ vypocet modulu """
        
    def angle (self):
        """ vypocet uhlu """

# instance
a = Complex(2.2, 3.3)
b = Complex(-4.1, 0.2)
# a.add(b)
c = a + b
print(id(a))
print(type(a))

print("a = {}".format(a))
print("b = {}".format(b))
print("c = {}".format(c))
</code>

===== Knihovna =====

<code python>
class Book:

    def __init__ (self, title, author, year):

        self.title = title
        self.author = author
        self.year = year
        self.sorting_order = 0 # 0 - title, 1 - surname, 2 - year

    def __str__ (self):

        return "title:  {}\nauthor: {}\nyear:   {}".format(self.title, self.author, self.year)

    def __lt__ (self, other):

        if self.sorting_order == 0:
            return self.title < other.title
        elif self.sorting_order == 1:
            a = self.author.split()
            b = other.author.split()
            return a[1] < b[1]
        elif self.sorting_order == 2:
            return self.year < other.year

knihovna = []
kniha_a = Book ("Honzikova cesta", "Bohumil Riha", 1954)
kniha_b = Book ("Cuk a Gek", "Arkadij Gajdar", 1935);

knihovna.append (kniha_a)
knihovna.append (kniha_b)
knihovna.append (Book("Robinson Crusoe", "Daniel Defoe", 1800))

knihovna = sorted(knihovna)

for i in range(len(knihovna)):
    print(knihovna[i])
    print("------------")
</code>