A queue is a First-In-First-Out (FIFO) data structure where elements are added at the rear and removed from the front.
Example Code (in Python):
class Queue:
def __init__(self):
self.items = []
def is_empty(self):
return len(self.items) == 0
def enqueue(self, item):
self.items.append(item)
def dequeue(self):
if not self.is_empty():
return self.items.pop(0)
else:
raise IndexError("dequeue from an empty queue")
def front(self):
if not self.is_empty():
return self.items[0]
else:
raise IndexError("front from an empty queue")
def size(self):
return len(self.items)
