{
"metadata": {
"name": "",
"signature": "sha256:0b4a52abc3f3246965d1e59241352e867e78e448510ae25e91b7d38dc4dcc202"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h1>Chapter 12: A Closer Look at Classes<h1>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.1, Page Number: 274<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class myclass:\n",
" __a=None\n",
" __b=None\n",
" def __init__(self,i,j):\n",
" self.__a=i\n",
" self.__b=j\n",
" def sum(self,x): #Friend function\n",
" return sum1(x)\n",
" \n",
"def sum1(x): \n",
" return x._myclass__a +x._myclass__b #accessing private members\n",
"\n",
"#Variable declaration\n",
"n=myclass(3,4)\n",
"\n",
"#Result\n",
"print n.sum(n)\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"7\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.2, Page Number: 275<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class c1:\n",
" __status=None\n",
" def set_status(self,state):\n",
" self.__status=state\n",
" \n",
"class c2:\n",
" __status=None\n",
" def set_status(self,state):\n",
" self.status=state\n",
" \n",
"#Friend function \n",
"def idle(a,b):\n",
" if a._c1__status or b._c2__status :\n",
" return 0\n",
" else:\n",
" return 1\n",
" \n",
"#variable declarations\n",
"def IDLE(): #Constants\n",
" return 0\n",
"def INUSE():\n",
" return 1\n",
"x=c1()\n",
"y=c2()\n",
"\n",
"x.set_status(IDLE())\n",
"y.set_status(IDLE())\n",
"\n",
"if idle(x,y):\n",
" print \"Screen Can Be Used.\"\n",
" \n",
"x.set_status(INUSE())\n",
"\n",
"if idle(x,y):\n",
" print \"Screen Can Be Used.\"\n",
"else:\n",
" print \"Pop-up In Use.\"\n",
" \n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Screen Can Be Used.\n",
"Pop-up In Use.\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.3, Page Number: 277<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"def IDLE(): \n",
" return 0\n",
"def INUSE():\n",
" return 1\n",
"\n",
"class c1:\n",
" __status=None\n",
" def set_status(self,state):\n",
" self.__status=state\n",
" def idle(self,b): #now a member of c1\n",
" if self.__status or b._c2__status :\n",
" return 0\n",
" else:\n",
" return 1\n",
" \n",
"class c2:\n",
" __status=None #IDLE if off INUSE if on screen\n",
" def set_status(self,state):\n",
" self.status=state\n",
" \n",
"#Variable declarations \n",
"x=c1()\n",
"y=c2()\n",
"\n",
"x.set_status(IDLE())\n",
"y.set_status(IDLE())\n",
"\n",
"if idle(x,y):\n",
" print \"Screen Can Be Used.\"\n",
" \n",
"x.set_status(INUSE())\n",
"\n",
"if idle(x,y):\n",
" print \"Screen Can Be Used.\"\n",
"else:\n",
" print \"Pop-up In Use.\"\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Screen Can Be Used.\n",
"Pop-up In Use.\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.4, Page Number: 278<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"import time,string\n",
"\n",
"class timer:\n",
" __seconds=None\n",
" \n",
" def __init__(self,t1,t2=None):\n",
" if t2==None:\n",
" if isinstance(t1,int): #seconds specified as an integer\n",
" self.__seconds=t1\n",
" else: #seconds specified as a string\n",
" self.__seconds=string.atoi(t1)\n",
" else: #time in minutes and seconds\n",
" self.__seconds=t1*60+t2\n",
" \n",
" def run(self):\n",
" t1=time.clock()\n",
" while (time.clock()-t1)<self.__seconds:\n",
" a=10\n",
" print time.clock()-t1\n",
" \n",
" \n",
"a=timer(10)\n",
"b=timer(\"20\")\n",
"c=timer(1,10)\n",
"a.run() #count 10 seconds\n",
"b.run() #count 20 seconds\n",
"c.run() #count 1 minute,10 seconds\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10.0000009774\n",
"20.0000009774"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"70.0000004887"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.5, Page Number: 280<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import time,string\n",
"\n",
"class timer:\n",
" __seconds=None\n",
" \n",
" def __init__(self,t1,t2=None):\n",
" if t2==None:\n",
" if isinstance(t1,int): #seconds specified as an integer\n",
" self.__seconds=t1\n",
" else: #seconds specified as a string\n",
" self.__seconds=string.atoi(t1)\n",
" else: #time in minutes and seconds\n",
" self.__seconds=t1*60+t2\n",
" \n",
" def run(self):\n",
" t1=time.clock()\n",
" while (time.clock()-t1)<self.__seconds:\n",
" a=10\n",
" print time.clock()-t1\n",
" \n",
"a=timer(10)\n",
"a.run()\n",
"\n",
"print \"Enter number of seconds: \"\n",
"str=\"20\"\n",
"b=timer(str) #initialize at the run time\n",
"c.run()\n",
"\n",
"print \"Enter minutes and seconds: \"\n",
"min=1\n",
"sec=10\n",
"c=timer(min,sec) #initialize at the run time\n",
"c.run()\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10.0000004887\n",
"Enter number of seconds: \n",
"70.0000009774"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"Enter minutes and seconds: \n",
"70.0000009774"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.6, Page Number: 282<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class myclass:\n",
" __a=None #private members\n",
" __b=None\n",
" def setab(self,i,j): #publc functons\n",
" self.__a=i\n",
" self.__b=j\n",
" def showab(self):\n",
" print \"a is \",self.__a\n",
" print \"b is \",self.__b\n",
"\n",
"#Variable declaration\n",
"ob1 = myclass()\n",
"ob2 = myclass()\n",
"\n",
"#Intalizing\n",
"ob1.setab(10,20)\n",
"ob2.setab(0,0)\n",
"\n",
"print \"ob1 before assignment: \"\n",
"ob1.showab()\n",
"print \"ob2 before assignment: \"\n",
"ob2.showab()\n",
"\n",
"ob2 = ob1 #assign ob1 to ob2\n",
"\n",
"#Result\n",
"print \"ob1 after assignment: \"\n",
"ob1.showab()\n",
"print \"ob2 after assignment: \"\n",
"ob2.showab()\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"ob1 before assignment: \n",
"a is 10\n",
"b is 20\n",
"ob2 before assignment: \n",
"a is 0\n",
"b is 0\n",
"ob1 after assignment: \n",
"a is 10\n",
"b is 20\n",
"ob2 after assignment: \n",
"a is 10\n",
"b is 20\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.7, Page Number: 283<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"from copy import deepcopy\n",
" \n",
"class OBJ:\n",
" def set_i(self,x):\n",
" self.__i=x\n",
" def out_i(self):\n",
" print self.__i,\n",
" \n",
"def f(x):\n",
" x=deepcopy(x)\n",
" x.out_i() #outputs 10\n",
" x.set_i(100) #this affects only local copy\n",
" x.out_i() #outputs 100\n",
" \n",
"#Variable declaration\n",
"o=OBJ()\n",
"o.set_i(10)\n",
"f(o) \n",
"o.out_i() #still outputs 10, value of i unchanged\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10 100 10\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.8, Page Number: 284<h3> "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class myclass: \n",
" def __init__(self,i):\n",
" self.__val=i\n",
" print \"Constructing\"\n",
" def __del__(self):\n",
" print \"Destructing\"\n",
" def getval(self):\n",
" return self.__val\n",
" \n",
"def display(ob):\n",
" print ob.getval()\n",
"\n",
"#Varable declaration\n",
"a=myclass(10)\n",
"\n",
"display(a)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Constructing\n",
"Destructing\n",
"10\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.9, Page Number: 286<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from ctypes import *\n",
"\n",
"class myclass:\n",
" def __init__(self,i):\n",
" print \"Allocating p\"\n",
" self.p=pointer(c_int(i))\n",
" def __del__(self):\n",
" print \"Freeing p\"\n",
" def getval(self):\n",
" return self.p[0]\n",
" \n",
"def display(ob):\n",
" print ob.getval()\n",
"\n",
"#Variable declaration\n",
"a=myclass(10)\n",
"\n",
"display(a)\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Allocating p\n",
"10\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.10, Page Number: 287<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"from ctypes import *\n",
"class myclass:\n",
" def __init__(self,i):\n",
" print \"Allocating p\"\n",
" self.p=pointer(c_int(i))\n",
" def __del__(self):\n",
" print \"Freeing p\"\n",
" def getval(self):\n",
" return self.p[0]\n",
" \n",
"def display(ob):\n",
" print ob[0].getval()\n",
"\n",
"#Variable declaration\n",
"a=[]\n",
"a.append(myclass(10))\n",
"\n",
"display(a)\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Freeing p\n",
"Allocating p\n",
"10\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.11, Page Number: 288<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class sample:\n",
" __s=None\n",
" def show(self):\n",
" print self.__s\n",
" def set(self,str):\n",
" self.__s=str\n",
"\n",
"#Return an object of type sample\n",
"def input():\n",
" str=sample()\n",
" instr = \"Hello\" #User input\n",
" str.set(instr)\n",
" return str\n",
"\n",
"#Variable declaration\n",
"ob=sample()\n",
"\n",
"#assign returned object to ob\n",
"ob=input()\n",
"\n",
"#Result\n",
"ob.show()\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Hello\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.12, Page Number: 289<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class sample:\n",
" __s=None\n",
" def __init__(self):\n",
" self.__s=0\n",
" def __del__(self): \n",
" print \"Freeing p\"\n",
" def show(self):\n",
" print self.__s\n",
" def set(self,str):\n",
" self.__s=str\n",
" \n",
"#This function takes one object parameter\n",
"def input():\n",
" str=sample()\n",
" instr=\"Hello\" #User input\n",
" str.set(instr)\n",
" return str\n",
"\n",
"#Variable declaration\n",
"ob=sample()\n",
"\n",
"#assign returned object to ob\n",
"ob=input()\n",
"\n",
"#Result\n",
"ob.show()\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Freeing p\n",
"Freeing p\n",
"Hello\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.13, Page Number: 292<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class myclass:\n",
" __p=None\n",
" def __init__(self,i):\n",
" if isinstance(i,int):\n",
" print \"Allocating p\"\n",
" self.__p=i\n",
" else:\n",
" print \"Copy constructor called\"\n",
" self.__p=i.getval()\n",
" def __del__(self): \n",
" print \"Freeing p\"\n",
" def getval(self):\n",
" return self.__p\n",
" \n",
"#This function takes one object parameter\n",
"def display(ob):\n",
" print ob.getval()\n",
"\n",
"#Variable declaration\n",
"ob=myclass(10)\n",
"\n",
"#Result\n",
"display(ob)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Allocating p\n",
"10\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.14, Page Number: 294<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"\n",
"class myclass:\n",
" __p=None\n",
" def __init__(self,i):\n",
" if isinstance(i,int):\n",
" print \"Allocating p\"\n",
" self.__p=i\n",
" else:\n",
" print \"Copy constructor called\"\n",
" self.__p=i.getval()\n",
" def __del__(self): \n",
" print \"Freeing p\"\n",
" def getval(self):\n",
" return self.__p\n",
" \n",
"\n",
"#Variable declaration\n",
"a=myclass(10) #calls normal constructor\n",
"b=myclass(a) #calls copy constructor\n",
"\n",
"\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Allocating p\n",
"Copy constructor called\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.15, Page Number: 295<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class myclass:\n",
" def __init__(self,i=0):\n",
" if isinstance(i,int):\n",
" print \"Normal constructor\"\n",
" else:\n",
" print \"Copy constructor\"\n",
"\n",
"\n",
"#Variable declaration\n",
"a=myclass() #calls normal constructor\n",
"\n",
"f=myclass()\n",
"a=myclass(f) #Invoke copyconstructor\n",
"\n",
"\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Normal constructor\n",
"Normal constructor\n",
"Copy constructor\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 12.16, Page Number: 297<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class c1:\n",
" def __init__(self):\n",
" self.__i=None\n",
" def load_i(self,val):\n",
" self.__i=val\n",
" def get_i(self):\n",
" return self.__i\n",
" \n",
"#Variable declaration \n",
"o=c1()\n",
"\n",
"o.load_i(100)\n",
"\n",
"#Result\n",
"print o.get_i()\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"100\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}