import math

class Student:
    '''A student with a name, age, and major.'''

    def __init__(self, name, age, major):
        '''Initializes the student object.'''
        self.name = name
        self.age = age
        self.major = major


    def birthyear(self):
        '''Return the birthyear of the student'''
        return 2015 - self.age


    def switch_major(self, new_major):
        '''Change the student's major to new_major and print a message
        saying it was done.'''
        self.major = new_major
        print(self.name + " changed major to " + self.major)


class LineSegment:
    '''A line segment class consisting of two points.'''

    def __init__(self, point1, point2):
        '''Initialize the line segment between point1 and point2'''
        self.startpoint = point1
        self.endpoint = point2


    def slope(self):
        '''Return the slope of the line'''
        change_y = self.endpoint[1] - self.startpoint[1]
        change_x = self.endpoint[0] - self.startpoint[0]
        return change_y / change_x


    def length(self):
        '''Return the length of the line'''
        return math.sqrt(
            (self.endpoint[0] - self.startpoint[0]) ** 2 +
            (self.endpoint[1] - self.startpoint[1]) ** 2)