不确定解决方案是否适用于python类

Question

Here is the question; create a car class with the following data attributes

__year_model
__make
__speed

The class should have an __init__ method that accepts the car's year model and make as argument. The value should be assigned to the objects __year_model and __make attributes . It should assign 0 to the __speed data attribute

It should also have the following method:

accelerate: accelerate should add 5 to the speed data attribute each time it is called.

brake: this method should subtract 5 from the speed

get_speed: this should display the current speed

Next, design a program that creates a Car object, and then calls the accelerate method five times. After each call to the accelerate method, get the current speed of the car and display it. Then call the brake method five times. After each call to the brake method, get the current speed of the car and display it.

class Car:
    def __init__(self,year_model,make,speed):
        self.year_mode = year_model
        self.make = make
        self.speed = 0

    def accelerate(self,accelerate):
        self.accelerate = accelerate
        speed = 0
        for x in range(5):
            speed = speed + 5
            print speed

    def brake(self,brake):
        self.brake = brake
        speed = 0
        for x in range(5):
            brake = brake - 5
            print brake

    def get_speed(self):
        return self.speed


test = Car(2006,'Honda',100)

I know test is the instance. Is it also the object? Thank you

Answer 1

Yes, test is an object, ie an instance of a class is an object.

Your class needs some work. According to the spec, speed is not supposed to be passed to __init__() . Remove that and initialise self.__speed to 0 in __init__() .

accelerate() and brake() are not supposed to take arguments - each method should either increase the current speed by 5, or reduce the speed by 5. Therefore these methods do not require any arguments (other than self ).

So accelerate() should be this:

def accelerate(self):
    self.__speed += 5    # shorthand for self.speed = self.speed + 5

which simply increases the speed by 5 each time it is called. Note that self is used so that the member __speed is incremented, not some temporary local varible. You can do the same for brake() .

Other than that, add the tests that your assignment specifies: call accelerate 5 times printing the speed after each call. Similarly for the brake method. Does the output agree with what you would expect?

Test like this:

car = Car(2006,'Honda')

for i in range(5):
    car.accelerate()
    print(car.get_speed())

for i in range(5):
    car.brake()
    print(car.get_speed())

Oh, and name your members as per the spec: __speed , not speed etc.