def lose_life(self): """Decrements a cat's life by 1. When lives reaches zero, 'is_alive' becomes False. If this is called after lives has reached zero, print out that the cat has no more lives to lose. """ "*** YOUR CODE HERE ***"
时间: 2024-03-02 17:48:07 浏览: 34
It seems like this is an incomplete function definition, and the implementation needs to be filled in. Here's one possible implementation:
```
def lose_life(self):
if self.lives > 0:
self.lives -= 1
if self.lives == 0:
self.is_alive = False
else:
print("The cat has no more lives to lose.")
```
This implementation checks if the cat still has lives left, decrements the `lives` attribute by 1, and sets the `is_alive` attribute to `False` if `lives` reaches zero. If the function is called after the cat has already lost all its lives, it prints out a message to indicate that.
相关问题
Below is a skeleton for the Cat class, which inherits from the Pet class. To complete the implementation, override the init and talk methods and add a new lose_life method, such that its behavior matches the following doctests. We may change the implementation of Pet while testing your code, so make sure you use inheritance correctly.其中class Pet: def init(self, name, owner): self.is_alive = True # It's alive!!! self.name = name self.owner = owner def eat(self, thing): print(self.name + " ate a " + str(thing) + "!") def talk(self): print(self.name)
Sure, I understand your question. Here is the completed implementation for the Cat class:
```
class Cat(Pet):
def __init__(self, name, owner, lives=9):
Pet.__init__(self, name, owner)
self.lives = lives
def talk(self):
print('Meow!')
def lose_life(self):
if self.lives > 0:
self.lives -= 1
if self.lives == 0:
self.is_alive = False
else:
self.is_alive = False
```
This implementation overrides the `talk` method to print "Meow!" and adds a new `lose_life` method that decrements the cat's remaining lives and sets its `is_alive` attribute to `False` if it runs out of lives.
Here are some doctests to verify the implementation:
```
>>> c = Cat('Fluffy', 'John')
>>> c.name
'Fluffy'
>>> c.owner
'John'
>>> c.is_alive
True
>>> c.talk()
Meow!
>>> c.eat('fish')
Fluffy ate a fish!
>>> c.lives
9
>>> c.lose_life()
>>> c.is_alive
True
>>> c.lives
8
>>> c.lose_life()
>>> c.lives
7
>>> c.lose_life() # repeat 6 more times until lives reach 0
>>> c.lose_life()
>>> c.lose_life()
>>> c.lose_life()
>>> c.lose_life()
>>> c.lose_life()
>>> c.lose_life()
>>> c.is_alive
False
>>> c.lose_life() # does nothing, cat is already dead
>>> c.is_alive
False
```
Called when the last reference to the mm is dropped: either by a lazy thread or by mmput. Free the page directory and the mm.
In the Linux kernel, the function called when the last reference to the mm is dropped is `mmput()`. This function decrements the reference count of the mm and releases it if the count reaches zero. When the mm is released, the function `mm_release()` is called. This function is responsible for freeing the page directory and the mm.
Here are the steps involved in freeing the page directory and the mm:
1. First, you need to obtain the page table directory pointer (pgd) from the mm.
```
pgd_t *pgd = mm->pgd;
```
2. Next, you need to release the page table pages by calling the function `pgd_free()`. This function takes the pgd pointer and the address space identifier (asid) as arguments.
```
pgd_free(mm, pgd, mm->asid);
```
Note that the asid is a unique identifier for the address space that is used to flush the TLB (Translation Lookaside Buffer) entries.
3. Finally, you can release the memory used by the mm by calling the function `kmem_cache_free()`. This function takes the pointer to the memory block and the cache descriptor as arguments.
```
kmem_cache_free(mm_cachep, mm);
```
Here, `mm_cachep` is the cache descriptor for the mm_struct cache.
That's it! You have now freed the page directory and the mm in the Linux kernel.
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