curriculum/challenges/english/blocks/learn-encapsulation-by-building-a-projectile-trajectory-calculator/6633b4d3271d5b3aea1c1195.md
Now it's time for the graph. Create a method create_trajectory and replace the last print call at the bottom of your code with print(graph.create_trajectory()).
As the first step of this new method, make a local copy of the coordinates but where all the values are rounded to integers. Save this new version of the coordinates in a variable named rounded_coords, and return this variable.
You should define a method named create_trajectory.
({
test: () => assert(runPython(
`_Node(_code).find_class('Graph').has_function('create_trajectory')`
))
})
You should replace print(graph.create_coordinates_table()) with print(graph.create_trajectory()).
({
test: () => runPython(`
prints = _Node(_code).find_calls('print')
assert all(not p.is_equivalent('print(graph.create_coordinates_table())') for p in prints), "print(graph.create_coordinates_table()) should not be present"
assert any(p.is_equivalent('print(graph.create_trajectory())') for p in prints), "print(graph.create_trajectory()) not found"
`)
})
The function should return rounded_coords.
({
test: () => runPython(`
assert _Node(_code).find_class('Graph').find_function('create_trajectory').has_return('rounded_coords'), "return rounded_coords missing"
`)
})
The rounded_coords variable should contain the rounded coordinates.
({
test: () => {
runPython(`
ball = Projectile(10, 3, 45)
coordinates = ball.calculate_all_coordinates()
graph = Graph(coordinates)
assert [(round(x), round(y)) for x,y in coordinates] == graph.create_trajectory(), "coordinates are not rounded correctly"
`)
}
})
import math
GRAVITATIONAL_ACCELERATION = 9.81
PROJECTILE = "∙"
x_axis_tick = "T"
y_axis_tick = "⊣"
class Projectile:
__slots__ = ('__speed', '__height', '__angle')
def __init__(self, speed, height, angle):
self.__speed = speed
self.__height = height
self.__angle = math.radians(angle)
def __str__(self):
return f'''
Projectile details:
speed: {self.speed} m/s
height: {self.height} m
angle: {self.angle}°
displacement: {round(self.__calculate_displacement(), 1)} m
'''
def __calculate_displacement(self):
horizontal_component = self.__speed * math.cos(self.__angle)
vertical_component = self.__speed * math.sin(self.__angle)
squared_component = vertical_component**2
gh_component = 2 * GRAVITATIONAL_ACCELERATION * self.__height
sqrt_component = math.sqrt(squared_component + gh_component)
return horizontal_component * (vertical_component + sqrt_component) / GRAVITATIONAL_ACCELERATION
def __calculate_y_coordinate(self, x):
height_component = self.__height
angle_component = math.tan(self.__angle) * x
acceleration_component = GRAVITATIONAL_ACCELERATION * x ** 2 / (
2 * self.__speed ** 2 * math.cos(self.__angle) ** 2)
y_coordinate = height_component + angle_component - acceleration_component
return y_coordinate
def calculate_all_coordinates(self):
return [
(x, self.__calculate_y_coordinate(x))
for x in range(math.ceil(self.__calculate_displacement()))
]
@property
def height(self):
return self.__height
@property
def angle(self):
return round(math.degrees(self.__angle))
@property
def speed(self):
return self.__speed
@height.setter
def height(self, n):
self.__height = n
@angle.setter
def angle(self, n):
self.__angle = math.radians(n)
@speed.setter
def speed(self, s):
self.__speed = s
def __repr__(self):
return f'{self.__class__}({self.speed}, {self.height}, {self.angle})'
class Graph:
__slots__ = ('__coordinates')
def __init__(self, coord):
self.__coordinates = coord
def __repr__(self):
return f"Graph({self.__coordinates})"
def create_coordinates_table(self):
table = '\n x y\n'
for x, y in self.__coordinates:
table += f'{x:>3}{y:>7.2f}\n'
return table
--fcc-editable-region--
ball = Projectile(10, 3, 45)
print(ball)
coordinates = ball.calculate_all_coordinates()
graph = Graph(coordinates)
print(graph.create_coordinates_table())
--fcc-editable-region--