{
"metadata": {
"name": "",
"signature": "sha256:fa5fb390e0208b333276a0ed5185d5e56d34940c09a52bd389b2d0242ea600f2"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 8: Harnessing polymorphism"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.1, Page No.134"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Base:\n",
" def Identify(self,adr):\n",
" print \"Base Class called by \",hex(adr)\n",
"\n",
"class SubA(Base):\n",
" def __init__(self,adr):\n",
" Base.Identify(self,adr)\n",
"class SubB(Base):\n",
" def __init__(self,adr):\n",
" Base.Identify(self,adr)\n",
"ptrA=1\n",
"ptrB=SubA(id(ptrA))\n",
"ptrC=2\n",
"ptrc=SubB(id(ptrC))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Base Class called by 0x12fd8e0\n",
"Base Class called by 0x12fd8d4\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.2, Page No.136"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Parent:\n",
" def Common(self):\n",
" print \"I am part of this family\"\n",
" def identify(self):\n",
" print \"I am the parent\"\n",
"\n",
"class Child(Parent):\n",
" def identify(self):\n",
" print \"I am the child\"\n",
" \n",
"class Grandchild(Child):\n",
" def identify(self):\n",
" print \"I am the grandchild\"\n",
" def Relate(self):\n",
" print \"Grandchild has parent and grandparent\"\n",
"\n",
"son=Child()\n",
"grandson=Grandchild()\n",
"parent=Parent()\n",
"print parent.Common(),\" \",son.identify()\n",
"print parent.Common(),\" \",grandson.identify()\n",
"print parent.Common(),\" \",parent.identify()\n",
"print grandson.Relate()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"I am part of this family\n",
"None I am the child\n",
"None\n",
"I am part of this family\n",
"None I am the grandchild\n",
"None\n",
"I am part of this family\n",
"None I am the parent\n",
"None\n",
"Grandchild has parent and grandparent\n",
"None\n"
]
}
],
"prompt_number": 18
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.3, Page No.138"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Bird:\n",
" def Talk(self):\n",
" print \"A Bird talks...\"\n",
" def Fly(self):\n",
" print \"A Bird flies...\"\n",
"class Pigeon(Bird):\n",
" def Talk(self):\n",
" print \"Coo!Coo!\"\n",
" def Fly(self):\n",
" print \"A Pigeon flies away...\"\n",
"class Chicken(Bird):\n",
" def Talk(self):\n",
" print \"Cluk!Cluk!\"\n",
" def Fly(self):\n",
" print \"I'm just a chicken- I can't fly!\"\n",
"pPigeon=Pigeon()\n",
"pChicken=Chicken()\n",
"pBird=Bird()\n",
"print \"\",pPigeon.Talk()\n",
"print \"\",pPigeon.Fly()\n",
"print \"\",pChicken.Talk()\n",
"print \"\",pChicken.Fly()\n",
"print \"\",pBird.Talk()\n",
"print \"\",pBird.Fly()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Coo!Coo!\n",
"None\n",
" A Pigeon flies away...\n",
"None\n",
" Cluk!Cluk!\n",
"None\n",
" I'm just a chicken- I can't fly!\n",
"None\n",
" A Bird talks...\n",
"None\n",
" A Bird flies...\n",
"None\n"
]
}
],
"prompt_number": 23
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.4, Page No. 140"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Bird:\n",
" def Talk(self):\n",
" return -1\n",
" def Fly(self):\n",
" return -1\n",
"class Pigeon(Bird):\n",
" def Talk(self):\n",
" print \"Coo!Coo!\"\n",
" def Fly(self):\n",
" print \"A Pigeon flies away...\"\n",
"class Chicken(Bird):\n",
" def Talk(self):\n",
" print \"Cluk!Cluk!\"\n",
" def Fly(self):\n",
" print \"I'm just a chicken- I can't fly!\"\n",
"pPegion=Pigeon()\n",
"pChicken=Chicken()\n",
"pPegion.Talk()\n",
"pChicken.Talk()\n",
"pBird=Bird()\n",
"data=pBird.Talk()\n",
"if data==-1:\n",
" print \"Error!-Program ended\"\n",
" exit()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Coo!Coo!\n",
"Cluk!Cluk!\n",
"Error!-Program ended\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.5, Page No.142"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Rect:\n",
" height=0\n",
" width=0\n",
" def __init__(self,initWidth,initHeight):\n",
" self.height=initHeight\n",
" self.width=initWidth\n",
" def getArea(self):\n",
" return self.height*self.width\n",
" def getEdge(self):\n",
" return ((2*self.height)+(2*self.width)) \n",
" def Draw(self):\n",
" for i in range(0,self.height):\n",
" for j in range(0,self.width):\n",
" print \"X\",\n",
" print \"\\n\"\n",
"\n",
"pQuad=Rect(7,3)\n",
"pSquare=Rect(5,5)\n",
"\n",
"pQuad.Draw()\n",
"print \"Area is:\",pQuad.getArea()\n",
"print \"Perimeter is:\",pQuad.getEdge()\n",
"\n",
"pSquare.Draw()\n",
"print \"Area is:\",pSquare.getArea()\n",
"print \"Perimeter is:\",pSquare.getEdge()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"X X X X X X X \n",
"\n",
"X X X X X X X \n",
"\n",
"X X X X X X X \n",
"\n",
"Area is: 21\n",
"Perimeter is: 20\n",
"X X X X X \n",
"\n",
"X X X X X \n",
"\n",
"X X X X X \n",
"\n",
"X X X X X \n",
"\n",
"X X X X X \n",
"\n",
"Area is: 25\n",
"Perimeter is: 20\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.6, Page No.144"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Boat:\n",
" length=0\n",
" def getLength(self):\n",
" return self.length\n",
"class Sailboat(Boat):\n",
" mast=0\n",
" def getMast(self):\n",
" return self.mast\n",
"class Laser(Sailboat):\n",
" def __init__(self):\n",
" self.mast=19\n",
" self.length=35\n",
" def Model(self):\n",
" print \"Laser Classic:\"\n",
" def Boom(self):\n",
" print \"Boom: 14ft\"\n",
"pLaser=Laser()\n",
"pLaser.Model()\n",
"print \"Length:\",pLaser.getLength(),\"ft\"\n",
"print \"Height:\",pLaser.getMast(),\"ft\"\n",
"pLaser.Boom()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Laser Classic:\n",
"Length: 35 ft\n",
"Height: 19 ft\n",
"Boom: 14ft\n"
]
}
],
"prompt_number": 17
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8.7, Page No.147"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"class Calculator:\n",
" status=\"true\"\n",
" num1=0.0\n",
" num2=0.0\n",
" oper='+'\n",
" def __init__(self):\n",
" self.status=\"true\"\n",
" def launch(self):\n",
" print \"***SUM CALCULATOR***\"\n",
" print \"Enter a number, an operator (+,-,*,/), and another number\\nEnter Zero to exit\"\n",
" def readInput(self):\n",
" print \">\",\n",
" self.num1=float(raw_input())\n",
" if self.num1==0:\n",
" self.status=\"false\"\n",
" else:\n",
" self.oper=raw_input()\n",
" self.num2=float(raw_input())\n",
" def writeOutput(self):\n",
" if self.status==\"true\":\n",
" if self.oper=='+':\n",
" print self.num1+self.num2\n",
" elif self.oper=='-':\n",
" print self.num1-self.num2\n",
" elif self.oper=='*':\n",
" print self.num1*self.num2\n",
" elif self.oper=='/':\n",
" if self.num2!=0:\n",
" print self.num1/self.num2\n",
" else:\n",
" print \"Cannot divide by zero\"\n",
" def run(self):\n",
" return self.status\n",
" \n",
" \n",
" \n",
" \n",
"pCalc=Calculator()\n",
"pCalc.launch()\n",
"while (pCalc.run()==\"true\"):\n",
" pCalc.readInput()\n",
" pCalc.writeOutput()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" ***SUM CALCULATOR***\n",
"Enter a number, an operator (+,-,*,/), and another number\n",
"Enter Zero to exit\n",
">"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"32\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"+\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"32\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
" 64.0\n",
">"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"5.25\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"-\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"8.75\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
" -3.5\n",
">"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"8\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"*\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"3\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
" 24.0\n",
">"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"20\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"/\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"5\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
" 4.0\n",
">"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"20\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"/\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"0\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Cannot divide by zero\n",
">"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"0\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n"
]
}
],
"prompt_number": 4
}
],
"metadata": {}
}
]
}