题解 | #【模板】队列#

import sys

class My_queue:
    def __init__(self):
        self.my_queue = []
    
    def push(self, input):
        self.my_queue.append(input)
    
    def is_Empty(self):
        return self.my_queue == []
    
    def pop(self):
        print(self.my_queue[0])
        self.my_queue.pop(0)
    
    def front(self):
        print(self.my_queue[0])


my_queue = My_queue()
for line in sys.stdin:
    line_one = line.split()
    if line_one[0] == "push":
        my_queue.push(int(line_one[1]))
    elif line_one[0] == "pop":
        if my_queue.is_Empty():
            print("error")
        else:
            my_queue.pop()
    elif line_one[0] == "front":
        if my_queue.is_Empty():
            print("error")
        else:
            my_queue.front()