CircularQueue.py

# CircularQueue.py
class CircularQueue :
    def __init__( self, capacity = 8 ) :
        self.capacity = capacity        # 용량(고정)
        self.array = [None] * capacity  # 요소들을 저장할 배열
        self.front = 0                  # 전단의 인덱스
        self.rear = 0                   # 후단의 인덱스

    def isEmpty( self ) :
       return self.front == self.rear

    def isFull( self ) :
       return self.front == (self.rear+1)%self.capacity

    def enqueue( self, item ):
        if not self.isFull():
            self.rear = (self.rear + 1) % self.capacity
            self.array[self.rear] = item

    def dequeue( self ):
        if not self.isEmpty():
            self.front = (self.front + 1) % self.capacity
            return self.array[self.front]

    def peek( self ):
        if not self.isEmpty():
            return self.array[(self.front + 1) % self.capacity]

    def size( self ) :
       return (self.rear - self.front + self.capacity) % self.capacity

    def __str__(self):
        if self.front < self.rear :
            return str(self.array[self.front+1:self.rear+1])
        else :
            return str(self.array[self.front+1:self.capacity] + \
                       self.array[0:self.rear+1] )


#======================================================================
if __name__ == "__main__":
    q = CircularQueue(8)
    q.enqueue('A')
    q.enqueue('B')
    q.enqueue('C')
    q.enqueue('D')
    q.enqueue('E')
    q.enqueue('F')
    print('A B C D E F 삽입: ', q)
    print('삭제 -->', q.dequeue())
    print('삭제 -->', q.dequeue())
    print('삭제 -->', q.dequeue())
    print('      3번의 삭제: ', q)
    q.enqueue('G')
    q.enqueue('H')
    q.enqueue('I')
    print('      G H I 삽입: ', q)