File size: 3,068 Bytes
93e3e00 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 | class Empty(Exception):
pass
class ArrayQueue:
DEFAULT_CAPACITY = 10
def __init__(self):
self._data = [None] * ArrayQueue.DEFAULT_CAPACITY
self._size = 0
self._front = 0
def __len__(self):
return self._size
def is_empty(self):
return self._size == 0
def first(self):
if self.is_empty():
raise Empty("Queue is Empty!")
return self._data[self._front]
def dequeue(self):
if self.is_empty():
raise Empty("Queue is Empty!")
answer = self._data[self._front]
self._data[self._front] = None
self._front = (self._front + 1) % len(self._data)
self._size -= 1
return answer
def enqueue(self, e):
if self._size == len(self._data):
self._resize(2 * len(self._data))
avail = (self._front + self._size) % len(self._data)
self._data[avail] = e
self._size += 1
print("Element", e, "is enqueued successfully")
def _resize(self, cap):
old = self._data
self._data = [None] * cap
walk = self._front
for k in range(self._size):
self._data[k] = old[walk]
walk = (walk + 1) % len(old)
self._front = 0
def main():
q = ArrayQueue()
while True:
print("\n\tQUEUE OPERATIONS")
print("1-Enqueue")
print("2-Dequeue")
print("3-First Element")
print("4-Length of Queue")
print("5-Is Empty")
print("6-Display Queue")
print("7-Exit")
try:
ch = int(input("Enter your choice: "))
if ch == 1:
e = int(input("Enter an element: "))
q.enqueue(e)
elif ch == 2:
print("The front element:", q.dequeue(), "is dequeued successfully")
elif ch == 3:
print("First element in the queue is", q.first())
elif ch == 4:
print("Queue length =", len(q))
elif ch == 5:
if q.is_empty():
print("Queue is empty!")
else:
print("Queue is not empty!")
elif ch == 6:
if q.is_empty():
print("Queue is empty!")
else:
print("Queue elements (front to rear):")
index = q._front
print("|", end=" ")
for _ in range(len(q)):
print(q._data[index], "|", end=" ")
index = (index + 1) % len(q._data)
print()
elif ch == 7:
print("Program exited")
break
else:
print("Invalid choice")
except Empty as e:
print(e)
except ValueError:
print("Please enter a valid number")
if __name__ == "__main__":
main()
|