Learn Encapsulation by Building a Projectile Trajectory Calculator - Step 11

Python
1

Tell us what’s happening:

What am I doing to cause my string representation Projectile error? I have re-read every related forum post, w3c schools, …etc, and I remain confused

Your code so far


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:\n
        \n speed: {self.__speed} m/s\n
        \n height: {self.__height} m\n
        \n angle: {round(math.degrees(self.__angle))}\n
        \n displacement: {round(self.__calculate_displacement(), 1)} m\n
        
Projectile details:
speed: {self.__speed} m/s
height: {self.__height} m
angle: {round(math.degrees(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

ball = Projectile(10, 3, 45)
print(ball)
coordinates = ball.calculate_all_coordinates()
    ```

```py
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)

# User Editable Region

    def __str__(self):
        return f'''
        Projectile details:\n
        \n speed: {self.__speed} m/s\n
        \n height: {self.__height} m\n
        \n angle: {round(math.degrees(self.__angle))}\n
        \n displacement: {round(self.__calculate_displacement(), 1)} m\n
        
Projectile details:
speed: {self.__speed} m/s
height: {self.__height} m
angle: {round(math.degrees(self.__angle))}°
displacement: {round(self.__calculate_displacement(), 1)} m
'''

# User Editable Region


    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

ball = Projectile(10, 3, 45)
print(ball)
coordinates = ball.calculate_all_coordinates()

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Challenge Information:

Learn Encapsulation by Building a Projectile Trajectory Calculator - Step 11

1 Like
2

Hi @Greg23111

You posted two sets of code.
In both sets, you added new line characters.
Please reset the step to restore the seed code.

Edit the str method to not reference the attributes anymore, but to use the getters.

Happy coding

1 Like