# 为了统计学生人数，可以给 Student 类增加一个类属性，每创建一个实例，该属性自动增加
class Student(object):
    count = 0
    def __init__(self, name):
        self.name = name
        Student.count += 1

s = Student('lilei')
print(s.count)
s = Student('wang')
print(s.count)
s = Student("hahah")
print(s.count)
s = Student('hong')
print(s.count)
s = Student('zhang')
print(s.count)