{
 "metadata": {
  "name": "ch12"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Chapter 12: Composition and Inheritance"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.1, Page no: 273"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Person:\n",
      "    def __init__(self,n=\"\",nat=\"U.S.A.\",s=1):\n",
      "        self.name = n\n",
      "        self.nationality = nat\n",
      "        self.sex = s\n",
      "\n",
      "    def printName(self):\n",
      "        print  self.name,\n",
      "    \n",
      "    def printNationality(self):\n",
      "        print  self.nationality,\n",
      "\n",
      "creator = Person(\"Bjarne Stroustrup\", \"Denmark\")\n",
      "print \"The creator of C++ was \" ,\n",
      "creator.printName() \n",
      "print \", who was born in \" ,\n",
      "creator.printNationality() \n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The creator of C++ was  Bjarne Stroustrup , who was born in  Denmark\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.2, Page no: 274"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "\n",
      "class Date:\n",
      "    def __init__(self,m=0,d=0,y=0):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "        \n",
      "    def setDate(self,m,d,y):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "    # Python doesn't have >> operator for input so we are just using input function\n",
      "    def input(self):\n",
      "        self.month = int(raw_input())        \n",
      "        self.day = int(raw_input())\n",
      "        self.year = int(raw_input())        \n",
      "    \n",
      "    # Python doesn't have << operator for output so we are just using print function\n",
      "    def print_(self):\n",
      "        monthName = [\"\", \"January\",\"February\",\"March\", \"April\", \"May\", \"June\",\\\n",
      "                         \"July\", \"August\",\"September\", \"October\", \"November\",\\\n",
      "                             \"December\"]\n",
      "        print monthName[self.month] , self.day , \",\" , self.year\n",
      "\n",
      "peace =  Date(11,11,1918)\n",
      "print \"World War I ended on \" ,\n",
      "peace.print_()\n",
      "peace.setDate(8,14,1945)\n",
      "print \"World War II ended on \" ,\n",
      "peace.print_()\n",
      "print \"Enter month, day, and year: \"\n",
      "date = Date()\n",
      "date.input()\n",
      "print \"The date is \" , \n",
      "date.print_()\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "World War I ended on  November 11 , 1918\n",
        "World War II ended on  August 14 , 1945\n",
        "Enter month, day, and year: \n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "7\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "4\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "1976\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The date is  July 4 , 1976\n"
       ]
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.3, Page no: 274"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Date:\n",
      "    def __init__(self,m=0,d=0,y=0):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "        \n",
      "    def setDate(self,m,d,y):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "    # Python doesn't have >> operator for input so we are just using input function\n",
      "    def input(self):\n",
      "        self.month = int(raw_input())        \n",
      "        self.day = int(raw_input())\n",
      "        self.year = int(raw_input())        \n",
      "    \n",
      "    # Python doesn't have << operator for output so we are just using print function\n",
      "    def print_(self):\n",
      "        monthName = [\"\", \"January\",\"February\",\"March\", \"April\", \"May\", \"June\",\\\n",
      "                         \"July\", \"August\",\"September\", \"October\", \"November\",\\\n",
      "                             \"December\"]\n",
      "        print monthName[self.month] , self.day , \",\" , self.year\n",
      "\n",
      "class Person:\n",
      "    def __init__(self,n=\"\",s=0,nat=\"U.S.A.\"):\n",
      "        self.name = n\n",
      "        self.nationality = nat\n",
      "        self.sex = s\n",
      "        self.dob = Date()\n",
      "        self.dod = Date()\n",
      "    def setDOB(self,m,d,y):\n",
      "        self.dob.setDate(m,d,y)\n",
      "    def setDOD(self,m,d,y):\n",
      "        self.dod.setDate(m,d,y)\n",
      "    def printName(self):\n",
      "        print  self.name,\n",
      "    def printNationality(self):\n",
      "        print  self.nationality,\n",
      "    def printDOB(self):\n",
      "        self.dob.print_()\n",
      "    def printDOD(self):\n",
      "        self.dod.print_()\n",
      "\n",
      "author = Person(\"Thomas Jefferson\", 1)\n",
      "author.setDOB(4,13,1743)\n",
      "author.setDOD(7,4,1826)\n",
      "print \"The author of the Declaration of Independence was \",\n",
      "author.printName()\n",
      "print \".\\nHe was born on \",\n",
      "author.printDOB()\n",
      "print \" and died on \",\n",
      "author.printDOD()\n",
      "\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The author of the Declaration of Independence was  Thomas Jefferson .\n",
        "He was born on  April 13 , 1743\n",
        " and died on  July 4 , 1826\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.4, Page no: 276"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Date:\n",
      "    def __init__(self,m=0,d=0,y=0):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "        \n",
      "    def setDate(self,m,d,y):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "    # Python doesn't have >> operator for input so we are just using input function\n",
      "    def input(self):\n",
      "        self.month = int(raw_input())        \n",
      "        self.day = int(raw_input())\n",
      "        self.year = int(raw_input())        \n",
      "    \n",
      "    # Python doesn't have << operator for output so we are just using print function\n",
      "    def print_(self):\n",
      "        monthName = [\"\", \"January\",\"February\",\"March\", \"April\", \"May\", \"June\",\\\n",
      "                         \"July\", \"August\",\"September\", \"October\", \"November\",\\\n",
      "                             \"December\"]\n",
      "        print monthName[self.month] , self.day , \",\" , self.year\n",
      "\n",
      "class Person:\n",
      "    def __init__(self,n=\"\",s=0,nat=\"U.S.A.\"):\n",
      "        self.name = n\n",
      "        self.nationality = nat\n",
      "        self.sex = s\n",
      "        self.dob = Date()\n",
      "        self.dod = Date()\n",
      "    def setDOB(self,m,d,y):\n",
      "        self.dob.setDate(m,d,y)\n",
      "    def setDOD(self,m,d,y):\n",
      "        self.dod.setDate(m,d,y)\n",
      "    def printName(self):\n",
      "        print  self.name,\n",
      "    def printNationality(self):\n",
      "        print  self.nationality,\n",
      "    def printDOB(self):\n",
      "        self.dob.print_()\n",
      "    def printDOD(self):\n",
      "        self.dod.print_()\n",
      "\n",
      "class Student(Person):\n",
      "    def __init__(self,n,s=0,i=\"\"):\n",
      "        Person.__init__(self,n,s)\n",
      "        self.id = i\n",
      "        self.credits = 0\n",
      "        self.gpa = 0\n",
      "        self.dom = Date()\n",
      "\n",
      "    def setDOM(self,m,d,y):\n",
      "        self.dom.setDate(m, d, y)\n",
      "    def printDOM(self):\n",
      "        self.dom.print_()\n",
      "\n",
      "x = Student(\"Ann Jones\", 0, \"219360061\")\n",
      "x.setDOB(5, 13, 1977)\n",
      "x.setDOM(8, 29, 1995)\n",
      "x.printName()\n",
      "print \"\\n\\t Born: \" ,\n",
      "x.printDOB()\n",
      "print \"\\n\\tMatriculated: \",\n",
      "x.printDOM()\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Ann Jones \n",
        "\t Born:  May 13 , 1977\n",
        "\n",
        "\tMatriculated:  August 29 , 1995\n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.5, Page no: 276"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Date:\n",
      "    def __init__(self,m=0,d=0,y=0):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "        \n",
      "    def setDate(self,m,d,y):\n",
      "        self.month = m\n",
      "        self.day = d\n",
      "        self.year = y\n",
      "    # Python doesn't have >> operator for input so we are just using input function\n",
      "    def input(self):\n",
      "        self.month = int(raw_input())        \n",
      "        self.day = int(raw_input())\n",
      "        self.year = int(raw_input())        \n",
      "    \n",
      "    # Python doesn't have << operator for output so we are just using print function\n",
      "    def print_(self):\n",
      "        monthName = [\"\", \"January\",\"February\",\"March\", \"April\", \"May\", \"June\",\\\n",
      "                         \"July\", \"August\",\"September\", \"October\", \"November\",\\\n",
      "                             \"December\"]\n",
      "        print monthName[self.month] , self.day , \",\" , self.year\n",
      "\n",
      "class Person:\n",
      "    def __init__(self,n=\"\",s=0,nat=\"U.S.A.\"):\n",
      "        self.name = n\n",
      "        self.nationality = nat\n",
      "        self.sex = s\n",
      "        self.dob = Date()\n",
      "        self.dod = Date()\n",
      "    def setDOB(self,m,d,y):\n",
      "        self.dob.setDate(m,d,y)\n",
      "    def setDOD(self,m,d,y):\n",
      "        self.dod.setDate(m,d,y)\n",
      "    def printName(self):\n",
      "        print  self.name,\n",
      "    def printNationality(self):\n",
      "        print  self.nationality,\n",
      "    def printDOB(self):\n",
      "        self.dob.print_()\n",
      "    def printDOD(self):\n",
      "        self.dod.print_()\n",
      "\n",
      "class Student(Person):\n",
      "    def __init__(self,n,s=0,i=\"\"):\n",
      "        Person.__init__(self,n,s)\n",
      "        self.id = i\n",
      "        self.credits = 0\n",
      "        self.gpa = 0\n",
      "        self.dom = Date()\n",
      "\n",
      "    def setDOM(self,m,d,y):\n",
      "        self.dom.setDate(m, d, y)\n",
      "    def printDOM(self):\n",
      "        self.dom.print_()\n",
      "    def printSex(self):\n",
      "        if self.sex == 1:\n",
      "            print \"male\"\n",
      "        else:\n",
      "            print 'female'\n",
      "\n",
      "x = Student(\"Ann Jones\", 0, \"219360061\")\n",
      "x.setDOB(5, 13, 1977)\n",
      "x.setDOM(8, 29, 1995)\n",
      "x.setDOD(7,4,1826)\n",
      "x.printName()\n",
      "print \"\\n\\t Born: \" ,  \n",
      "x.printDOB()\n",
      "print \"\\n\\t Sex: \" ,\n",
      "x.printSex()\n",
      "print \"\\n\\tMatriculated: \",\n",
      "x.printDOM()\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Ann Jones \n",
        "\t Born:  May 13 , 1977\n",
        "\n",
        "\t Sex:  female\n",
        "\n",
        "\tMatriculated:  August 29 , 1995\n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.6, Page no: 279"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class X:\n",
      "    def __init__(self):\n",
      "        self.a = 0\n",
      "    def f(self):\n",
      "        print \"X::f() executing\"\n",
      "class Y(X):\n",
      "    def __init__(self):\n",
      "        self.a = 0\n",
      "    def f(self):\n",
      "        print \"Y::f() executing\"\n",
      "x = X()\n",
      "x.a = 22\n",
      "x.f()\n",
      "print \"x.a = \" , x.a\n",
      "y = Y()\n",
      "y.a = 44\n",
      "# assigns 44 to the a defined in Y\n",
      "y._X__a = 66\n",
      "# assigns 66 to the a defined in X\n",
      "y.f()\n",
      "# invokes the f() defined in Y\n",
      "X.f(x)\n",
      "# invokes the f() defined in X\n",
      "print \"y.a = \" , y.a \n",
      "print \"y._X__a = \" , y._X__a \n",
      "z = y\n",
      "print \"z.a = \" , z._X__a \n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "X::f() executing\n",
        "x.a =  22\n",
        "Y::f() executing\n",
        "X::f() executing\n",
        "y.a =  44\n",
        "y._X__a =  66\n",
        "z.a =  66\n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.7, Page no: 280"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "Note : Python destuctor is called when program goes exit. So output may be differ than c.\n",
      "'''\n",
      "class X:\n",
      "    def __init__(self):\n",
      "        print \"X::X() constructor executing \"\n",
      "    def __del__(self):\n",
      "        print \"X::X() destructor executing \"\n",
      "\n",
      "class Y(X):\n",
      "    def __init__(self):\n",
      "        X.__init__(self)\n",
      "        print \"Y::Y() constructor executing \"\n",
      "    def __del__(self):\n",
      "        print \"Y::Y() destructor executing \"\n",
      "\n",
      "class Z(Y):\n",
      "    def __init__(self,i):\n",
      "        Y.__init__(self)\n",
      "        print \"Z::Z(\" , i , \") constructor executing \"\n",
      "    def __del__(self):\n",
      "        print \"Z::Z() destructor executing \"\n",
      "        \n",
      "\n",
      "Z = Z(44)\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "X::X() constructor executing \n",
        "Y::Y() constructor executing \n",
        "Z::Z( 44 ) constructor executing \n"
       ]
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.8, Page no: 281"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "Note : Python destuctor is called when program goes exit. So output may be differ than c.\n",
      "'''\n",
      "class Person:\n",
      "    def __init__(self,s):\n",
      "        self.name = s\n",
      "    def __del__(self):\n",
      "        pass\n",
      "\n",
      "class Student(Person):\n",
      "    def __init__(self,s,m):\n",
      "        Person.__init__(self,s)\n",
      "        self.major = m\n",
      "    def __del__(self):\n",
      "        pass\n",
      "x = Person(\"Bob\")\n",
      "y = Student(\"Sarah\", \"Biology\")\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 8
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.9, Page no: 282"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Person:\n",
      "    def __init__(self,n=\"\",s=0,nat=\"U.S.A.\"):\n",
      "        self.name = n\n",
      "        self.nationality = nat\n",
      "        self.sex = s\n",
      "        self.dob = Date()\n",
      "        self.dod = Date()\n",
      "    def setDOB(self,m,d,y):\n",
      "        self.dob.setDate(m,d,y)\n",
      "    def setDOD(self,m,d,y):\n",
      "        self.dod.setDate(m,d,y)\n",
      "    def printName(self):\n",
      "        print  self.name,\n",
      "    def printNationality(self):\n",
      "        print  self.nationality,\n",
      "    def printDOB(self):\n",
      "        self.dob.print_()\n",
      "    def printDOD(self):\n",
      "        self.dod.print_()\n",
      "    def setHSgraduate(self,g):\n",
      "        self.hs = g\n",
      "    def isHSgraduate(self):\n",
      "        return hs\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 9
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.10, Page no: 283"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "Note : By default all methods in python are virtual. so output would be differ than c.\n",
      "'''\n",
      "class X:\n",
      "    def f(self):\n",
      "        print \"X::f() executing\"\n",
      "class Y(X):\n",
      "    def f(self):\n",
      "        print \"Y::f() executing\"\n",
      "x = X()\n",
      "y = Y()\n",
      "p = x\n",
      "p.f()\n",
      "p = y\n",
      "p.f()\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "X::f() executing\n",
        "Y::f() executing\n"
       ]
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.11, Page no: 284"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Person:\n",
      "    def __init__(self,n):\n",
      "        self.name = n\n",
      "    def print_(self):\n",
      "        print 'My name is' , self.name\n",
      "\n",
      "class Student(Person):\n",
      "    def __init__(self,s,g):\n",
      "        Person.__init__(self,s)\n",
      "        self.gpa = g\n",
      "    def print_(self):\n",
      "        print 'My name is ',self.name, ' and my G.P.A. is', self.gpa\n",
      "\n",
      "class Professor(Person):\n",
      "    def __init__(self,s,n):\n",
      "        Person.__init__(self,s)\n",
      "        self.publs = n\n",
      "    def print_(self):\n",
      "        print 'My name is ', self.name,' and i have ' , self.publs,' publications.'\n",
      "\n",
      "x = Person(\"Bob\")\n",
      "p = x\n",
      "p.print_()\n",
      "y = Student(\"Tom\", 3.47)\n",
      "p = y\n",
      "p.print_()\n",
      "z = Professor(\"Ann\", 7)\n",
      "p = z\n",
      "p.print_()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "My name is Bob\n",
        "My name is  Tom  and my G.P.A. is 3.47\n",
        "My name is  Ann  and i have  7  publications.\n"
       ]
      }
     ],
     "prompt_number": 11
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.12, Page no: 285"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "This program is similar to Example 12.6:\n",
      "'''\n",
      "class X:\n",
      "    def __init__(self):\n",
      "        self.p = [0,0]\n",
      "        print 'X().',\n",
      "    def __del__(self):\n",
      "        print '~X().'\n",
      "\n",
      "class Y(X):\n",
      "    def __init__(self):\n",
      "        X.__init__(self)\n",
      "        self.q = []\n",
      "        for i in range(1023):\n",
      "            self.q.append(0)\n",
      "        print 'Y() : Y::q = ', hex(id(self.q)) ,'.',\n",
      "    def __del__(self):\n",
      "        print '~Y().'\n",
      "\n",
      "for i in range(8):\n",
      "    r = Y()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "X(). Y() : Y::q =  0x90d91cc . ~Y().\n",
        "X(). Y() : Y::q =  0x90c944c . ~Y().\n",
        "X(). Y() : Y::q =  0x90d91cc . ~Y().\n",
        "X(). Y() : Y::q =  0x90c944c . ~Y().\n",
        "X(). Y() : Y::q =  0x90d91cc . ~Y().\n",
        "X(). Y() : Y::q =  0x90c944c . ~Y().\n",
        "X(). Y() : Y::q =  0x90d91cc . ~Y().\n",
        "X(). Y() : Y::q =  0x90c944c . ~Y().\n"
       ]
      }
     ],
     "prompt_number": 13
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 12.13, Page no: 288"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "class Media:\n",
      "    def __init__(self):\n",
      "        self.title = ''\n",
      "    def print_(self):\n",
      "        pass\n",
      "    def id(self):\n",
      "        pass\n",
      "\n",
      "class Book(Media):\n",
      "    def __init__(self,a='',t=\"\",p=\"\",i=\"\"):\n",
      "        self.author = a\n",
      "        self.publisher = p\n",
      "        self.isbn = i\n",
      "        self.title = t\n",
      "    def print_(self):\n",
      "        print self.title , \" by \" , self.author\n",
      "    def id(self):\n",
      "        return self.isbn\n",
      "\n",
      "class CD(Media):\n",
      "    def __init__(self,t=\"\",c=\"\",m=\"\",n=\"\"):\n",
      "        self.composer = c\n",
      "        self.make = m\n",
      "        self.number = n\n",
      "        self.title = t\n",
      "    def print_(self):\n",
      "        print self.title , \", \" , self.composer\n",
      "    def id(self):\n",
      "        s = str(self.make) + ' ' + str(self.number)\n",
      "        return s\n",
      "\n",
      "class Magazine(Media):\n",
      "    def __init__(self,t=\"\",i=\"\",v=0, n=0):\n",
      "        self.issn = i\n",
      "        self.volume = v\n",
      "        self.number = n\n",
      "        self.title = t\n",
      "    def print_(self):\n",
      "        print self.title , \" Magazine, Vol. \", self.volume , \", No.\" , self.number\n",
      "    def id(self):\n",
      "        return self.issn\n",
      "\n",
      "book = Book(\"Bjarne Stroustrup\", \"The C++ Programming Language\",\"Addison-Wesley\", \"0-201-53992-6\")\n",
      "magazine = Magazine(\"TIME\", \"0040-781X\", 145, 23)\n",
      "cd = CD(\"BACH CANTATAS\", \"Johann Sebastian Bach\",\"ARCHIV\", \"D120541\")\n",
      "book.print_()\n",
      "print \"\\tid: \" , book.id() \n",
      "magazine.print_()\n",
      "print \"\\tid: \" , magazine.id() \n",
      "cd.print_()\n",
      "print \"\\tid: \" , cd.id()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The C++ Programming Language  by  Bjarne Stroustrup\n",
        "\tid:  0-201-53992-6\n",
        "TIME  Magazine, Vol.  145 , No. 23\n",
        "\tid:  0040-781X\n",
        "BACH CANTATAS ,  Johann Sebastian Bach\n",
        "\tid:  ARCHIV D120541\n"
       ]
      }
     ],
     "prompt_number": 14
    }
   ],
   "metadata": {}
  }
 ]
}