[python] queue.append(raw_input('Enter new string: ').strip())
#调用list的列表的pop()函数.pop(0)为列表的第一个元素
print 'Cannot pop from an empty queue!'
print 'Removed [', queue.pop(0) ,']'
CMDs = {'e': enQ, 'd': deQ, 'v': viewQ}
choice = raw_input(pr).strip()[0].lower()
except (EOFError, KeyboardInterrupt, IndexError):
print '\nYou picked: [%s]' % choice
print 'Invalid option, try again'
if __name__ == '__main__':