Object-Oriented Programming
- Complete a memory diagram for the following code listing.
1 class Dog:
2 name: str
3 age: int
4
5 def __init__(self, n: str, a:int):
6 self.name = n
7 self.age = a
8
9 def speak(self) -> None:
10 print(self.name + " says woof!")
11
12 def birthday(self) -> int:
13 self.age += 1
14 return self.age
15
16 class Cat:
17 name: str
18 age: int
19
20 def __init__(self, n: str, a:int):
21 self.name = n
22 self.age = a
23
24 def speak(self) -> None:
25 print(self.name + " says meow!")
26
27 def birthday(self) -> int:
28 self.age += 1
29 return self.age
30
31 rory: Dog = Dog(n = "Rory", a = 4)
32 print(rory.birthday())
33 miso: Cat = Cat("Miso", 2)
34 miso.speak()- Complete a memory diagram for the following code listing.
1 class Concert:
2 artist: str
3 seats: dict[str, bool]
4
5 def __init__(self, a: str, s: dict[str, bool]):
6 self.artist = a
7 self.seats = s
8
9 def assign_seats(self, wanted_seats: list[str], name: str) -> None:
10 for seat in wanted_seats:
11 if seat in self.seats:
12 available: bool = self.seats[seat]
13 if available:
14 print(f"{name} bought seat {seat} to see {self.artist}!")
15 self.seats[seat] = False
16 else:
17 print(f"Seat {seat} is unavailable :(")
18
19 lenovo_seats: dict[str, bool] = {"K1": True, "K2": True, "K3": False}
20 show: Concert = Concert(a = "Travisty", s = lenovo_seats)
21 show.assign_seats(wanted_seats = ["K2", "K3"], name = "Kay")SOLUTIONS
- Dog and Cat memory diagram solution (see the solution video here!).
- Concert memory diagram solution (see the solution video here!).
Magic Methods
- Diagram the following code snippet:
1 class Knight:
2 """A medieval Knight."""
3 name: str
4
5 def __init__(self, name: str):
6 self.name = name
7
8 def __str__(self) -> str:
9 return f"Sir {self.name}"
10
11 class Castle:
12 """A medieval castle with a drawbridge for crossing a surrounding moat and a guarding knight."""
13 guard: Knight
14 drawbridge_up: bool
15
16 def __init__(self, guard: Knight, bridge_up: bool):
17 self.guard = guard
18 self.drawbridge_up = bridge_up
19
20 def __str__(self) -> str:
21 if self.drawbridge_up:
22 return f"Guarded by {self.guard} and closed to outsiders!"
23 else:
24 return f"Guarded by {self.guard} but open to all!"
25
26 def open(self) -> None:
27 if self.drawbridge_up:
28 print("Let down the bridge!")
29 self.drawbridge_up = False
30 else:
31 print("Already open!")
32
33 def close(self) -> None:
34 if not self.drawbridge_up:
35 print("Pull up the bridge!")
36 self.drawbridge_up = True
37 else:
38 print("Already closed!")
39
40
41 lancelot: Knight = Knight("Lancelot")
42 my_castle: Castle = Castle(lancelot, False)
43 print(my_castle)
44 my_castle.close()
45 print(my_castle)SOLUTION
Recursive Structures
Create a memory diagram of the following code snippet:
1 """A messy linked list...""" 2 3 from __future__ import annotations 4 5 # Node class definition included for reference! 6 class Node: 7 value: int 8 next: Node | None 9 10 def __init__(self, val: int, next: Node | None): 11 self.value = val 12 self.next = next 13 14 def __str__(self) -> str: 15 rest: str 16 if self.next is None: 17 rest = "None" 18 else: 19 rest = str(self.next) 20 return f"{self.value} -> {rest}" 21 22 knight: Node = Node(3, None) 23 bishop: Node = Node(2, knight) 24 rook: Node = Node(1, bishop) 25 print(rook) 26 castle: Node = Node(0, bishop) 27 print(castle)
SOLUTION
