#!/usr/bin/python3

# Example of class usage in python.

# Let's define a new class to represent fraction numbers


class fraction(object):
    def __init__(self, numer, denom):
        self.numer = numer
        self.denom = denom

    def __str__(self):
        return str(self.numer) + ' / ' + str(self.denom)


    # Getters definition
    # We almost never want to directly manipulate the data inside objects,
    # so, we should (almost) always define getters and setters methods for data
    # manipulation inside a class

    def getNumer(self):
        return self.numer

    def getDenom(self):
        return self.denom

    def __add__(self, other):
        new_numer = (self.getNumer() * other.getDenom()) + \
                    (other.getNumer() * self.getDenom())
        new_denom = (self.getDenom() * other.getDenom())

        return fraction(new_numer, new_denom)

    def __sub__(self, other):
        new_numer = (self.getNumer() * other.getDenom()) - \
                    (other.getNumer() * self.getDenom())
        new_denom = (self.getDenom() * other.getDenom())

        return fraction(new_numer, new_denom)

    # Return the float representation of the fraction
    def convert(self):
        return self.getNumer() / self.getDenom()


# Set example

# Create a class to represent a set of numbers which are not allowed to be
# repeated

class Set(object):

    def __init__(self):
        self.set = []

    def insert(self, nval):
        if nval not in self.set:
            self.set.append(nval)
        else:
            raise ValueError(str(nval) + " is already in the set")

    def remove(self,nval):
        try:
            self.set.remove(nval)
        except:
            raise ValueError(str(nval) + " not found!")

    def member(self, nval):
        return nval in self.set

    def __str__(self):
        self.set.sort()

        result = ''

        for i in self.set:
            result += str(i) + ', '

        return '{' + result[:-2] + '}'