from random import randrange

class Student:
	
    def __init__(self, id_, name):
        self.id_ = id_
        self.name = name

    def enroll(self,section):
        section.enroll(self.id_)
	    
    def drop(self, section):
        section.drop(self.id_)

    def print_name(self):
        print "%s, id:%s" %(self.name,self.id_)

class Course:

    def __init__(self, name, section, instructor_name):
        self.name = name
        self.section = section
        self.i_name=instructor_name
        self.list = [0]
        self.list.remove(0)

    def enroll(self, student_id):
        self.list.append(student_id)
        print "Added one student"

    def drop(self, student_id):
        self.list.remove(student_id)

    def roster(self):
        print "the list of students in the %s (section %s) class:" %(self.name, self.section)
        #n=len(self.list)
        for i in self.list:
            print i

                

def main():
    s1 = Student(123,"Stuart Smith")
    s2 = Student(234,"Anna Clark")
    s3 = Student(132,"Mark Stone")
    s4 = Student(324,"Helen Jones")

    c2434=Course("MTH01",2434,"Natalia Novak")
    c3452=Course("MTH03",3452,"John Smith")

    s1.print_name()
    s2.print_name()
    s3.print_name()
    s4.print_name()

    s1.enroll(c2434) # using the variable's name to enroll, not the section #
    s2.enroll(c2434) #
    s3.enroll(c3452) #
    s4.enroll(c3452) #
    s1.enroll(c3452) #

    c2434.roster()
    c3452.roster()

    s1.drop(c2434) # using the variable's name to drop, not the section #
    s4.drop(c3452)

    c2434.roster()
    c3452.roster()    
    
        

main()