{
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"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h1>Chapter 11: Introducing the Class<h1>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.1, Page Number: 249<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class queue:\n",
" #Initialize the queue \n",
" def __init__(self):\n",
" self.__sloc=0\n",
" self.__rloc=-1\n",
" self.__q=[]\n",
" \n",
" #Put an integer into the queue\n",
" def qput(self,i):\n",
" if self.__sloc==100:\n",
" print \"Queue is full.\"\n",
" return\n",
" self.__sloc+=1\n",
" self.__q.append(i)\n",
" \n",
" #Get an integer from the queue\n",
" def qget(self):\n",
" if self.__rloc==self.__sloc:\n",
" print \"Queue underflow\"\n",
" return\n",
" self.__rloc+=1\n",
" return self.__q[self.__rloc] \n",
" \n",
"\n",
" \n",
"#Create two queue objects\n",
"b=queue()\n",
"a=queue()\n",
"\n",
"a.qput(10)\n",
"b.qput(19)\n",
"\n",
"a.qput(20)\n",
"b.qput(1)\n",
"\n",
"#Result\n",
"print \"Contents of queue a: \",\n",
"print a.qget(),' ',a.qget()\n",
"\n",
"print \"Contents of queue b: \",\n",
"print b.qget(),' ',b.qget()\n",
"\n",
"\n",
" \n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Contents of queue a: 10 20\n",
"Contents of queue b: 19 1\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.2, Page Number: 250<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
" \n",
"class myclass:\n",
" def __init__(self):\n",
" self.__a=None #private member\n",
" self.b=None #public member\n",
" #public functions\n",
" def setlab(self,i):\n",
" self.__a=i #refer to a\n",
" self.b=i*i #refer to b\n",
" return\n",
" def geta(self):\n",
" return self.__a #refer to a\n",
" def reset(self):\n",
" #call setlab using self\n",
" self.setlab(0) #the object is already known\n",
" \n",
" \n",
"ob=myclass()\n",
"ob.setlab(5) #set ob.a and ob.b\n",
"print \"ob after setlab(5): \",ob.geta(),' ',\n",
"print ob.b #can access b because it is public\n",
"\n",
"ob.b=20 #can access b because it is public\n",
"print \"ob after ob.b=20: \",\n",
"print ob.geta(),' ',ob.b\n",
"\n",
"ob.reset()\n",
"print \"ob after ob.reset(): \",ob.geta(),' ',ob.b\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"ob after setlab(5): 5 25\n",
"ob after ob.b=20: 5 20\n",
"ob after ob.reset(): 0 0\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.3, Page Number: 254<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class queue:\n",
" \n",
" #Constructor\n",
" def __init__(self): \n",
" self.__q=[]\n",
" self.__rloc=-1\n",
" self.__sloc=0\n",
" print \"Queue initialized\"\n",
" \n",
" #Destructor\n",
" def __del__(self):\n",
" print (\"Queue destroyed\")\n",
" \n",
" #Put an integer into the queue\n",
" def qput(self,i):\n",
" if self.__sloc == 100:\n",
" print \"Queue is full\"\n",
" return \n",
" self.__sloc+=1\n",
" self.__q.append(i)\n",
" \n",
" #Get an integer from the queue\n",
" def qget(self):\n",
" if self.__rloc==self.__sloc:\n",
" print \"Queue underflow\"\n",
" return\n",
" self.__rloc+=1\n",
" return self.__q[self.__rloc]\n",
" \n",
"#Create two queue objects\n",
"a=queue()\n",
"\n",
"\n",
"a.qput(10)\n",
"a.qput(20)\n",
"b=queue()\n",
"b.qput(19)\n",
"\n",
"b.qput(1)\n",
"\n",
"#Result\n",
"print a.qget(),' ',\n",
"print a.qget(),' ',\n",
"print b.qget(),' ',\n",
"print b.qget(),' '\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Queue initialized\n",
"Queue destroyed\n",
"Queue initialized\n",
"Queue destroyed\n",
"10 20 19 1 \n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.4, Page Number: 257<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class queue: \n",
" \n",
" #Constructor\n",
" def __init__(self,i): \n",
" self.__q=[]\n",
" self.__rloc=-1\n",
" self.__sloc=0\n",
" self.__who=i\n",
" print \"Queue \",self.__who,\" initialized.\"\n",
" \n",
" #Destructor\n",
" def __del__():\n",
" print \"Queue \",self.__who,\" destroyed\"\n",
" \n",
" #Put an integer into the queue\n",
" def qput(self,i):\n",
" if self.__sloc == 100:\n",
" print \"Queue is full\"\n",
" return \n",
" self.__sloc+=1\n",
" self.__q.append(i)\n",
" \n",
" #Get an integer from the queue\n",
" def qget(self):\n",
" if self.__rloc==self.__sloc:\n",
" print \"Queue underflow\"\n",
" return\n",
" self.__rloc+=1\n",
" return self.__q[self.__rloc]\n",
" \n",
"a=queue(1)\n",
"b=queue(2)\n",
"\n",
"a.qput(10)\n",
"b.qput(19)\n",
"\n",
"a.qput(20)\n",
"b.qput(1)\n",
"\n",
"#Result\n",
"print a.qget(),' ',\n",
"print a.qget(),' ',\n",
"print b.qget(),' ',\n",
"print b.qget(),' '\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Queue 1 initialized.\n",
"Queue destroyed\n",
"Queue 2 initialized.\n",
"Queue destroyed\n",
"10 20 19 1 \n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.5, Page Number: 258<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class widget:\n",
" \n",
" #Pass two arguments to the constructor\n",
" def __init__(self,a,b):\n",
" self.__i=a\n",
" self.__j=b\n",
" \n",
" def put_widget(self):\n",
" print self.__i,\" \",self.__j\n",
"\n",
"#Initializing\n",
"x=widget(10,20)\n",
"y=widget(0,0)\n",
"\n",
"x.put_widget()\n",
"y.put_widget()\n",
"\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10 20\n",
"0 0\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.6, Page Number: 259<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class myclass:\n",
" \n",
" #Constructor\n",
" def __init__(self,x):\n",
" self.a=x\n",
" #To get the vale of a\n",
" def get_a(self):\n",
" return self.a\n",
"\n",
"#Initializing\n",
"ob=myclass(4)\n",
"\n",
"#Result\n",
"print ob.get_a()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"4\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.7, Page Number: 260<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from ctypes import *\n",
"\n",
"class c1(Structure):\n",
" _fields_=[(\"__i\", c_int)] #private member\n",
" def get_i(self): #public finctions\n",
" return self.__i\n",
" def put_i(self,j):\n",
" self.__i=j\n",
"\n",
"#Variable declaration\n",
"s=c1()\n",
"\n",
"s.put_i(10)\n",
"\n",
"#Result\n",
"print s.get_i()\n",
" \n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.8, Page Number: 261<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class c1:\n",
" def __init__(self):\n",
" self.__i=None #private member\n",
" def get_i(self): #public finctions\n",
" return self.__i\n",
" def put_i(self,j):\n",
" self.__i=j\n",
"\n",
"#Variable declaration\n",
"s=c1()\n",
"\n",
"s.put_i(10)\n",
"\n",
"#Result\n",
"print s.get_i()\n",
" \n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.9, Page Number: 263<h3> "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from ctypes import *\n",
"\n",
"#Creates a union\n",
"class u_type(Union):\n",
" _fields_ = [(\"i\",c_short),\n",
" (\"ch\", c_char*2)]\n",
" #Constructor\n",
" def __init__(self,a):\n",
" self.i=a\n",
" \n",
" #Show the characters that comprise a short int.\n",
" def showchars(self):\n",
" print self.ch[0]\n",
" print self.ch[1]\n",
" \n",
" \n",
"u=u_type(1000)\n",
"\n",
"#Displays char of 1000\n",
"u.showchars()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\ufffd\n",
"\u0003\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.10, Page Number: 264<h3> "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class c1:\n",
" def __init__(self):\n",
" self.__i=None\n",
" def get_i(self):\n",
" return self.i\n",
" def put_i(self,j):\n",
" self.i=j\n",
"\n",
"#Variable declaration\n",
"s=c1()\n",
"\n",
"s.put_i(10)\n",
"\n",
"#Result\n",
"print s.get_i()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.11, Page Number: 265<h3> "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class c1:\n",
" def __init__(self):\n",
" self.__i=None\n",
" def get_i(self):\n",
" return self.i\n",
" def put_i(self,j):\n",
" self.i=j\n",
"\n",
"#Variable declaration\n",
"s=c1()\n",
"\n",
"s.put_i(10)\n",
"\n",
"#Result\n",
"print s.get_i()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.12, Page Number: 267<h3> "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class display:\n",
" def __init__(self):\n",
" width=None\n",
" height=None\n",
" res=None\n",
" def set_dim(self,w,h):\n",
" self.width=w\n",
" self.height=h\n",
" def get_dim(self):\n",
" return self.width,self.height\n",
" def set_res(self,r):\n",
" self.res=r\n",
" def get_res(self):\n",
" return self.res\n",
" \n",
"#Variable decleration\n",
"names=[\"low\",\"medium\",\"high\"] \n",
"(low,medium,high)=(0,1,2) #For enumeration type\n",
"w=None\n",
"h=None\n",
"display_mode=[]*3\n",
"\n",
"for i in range(3):\n",
" display_mode.append(display())\n",
"\n",
"#Initialize the array of objects using member functions\n",
"display_mode[0].set_res(low)\n",
"display_mode[0].set_dim(640,480)\n",
"\n",
"display_mode[1].set_res(medium)\n",
"display_mode[1].set_dim(800,600)\n",
"\n",
"display_mode[2].set_res(high)\n",
"display_mode[2].set_dim(1600,1200)\n",
"\n",
"#Result\n",
"print \"Available display modes: \"\n",
"for i in range(3):\n",
" print names[display_mode[i].get_res()],\" : \",\n",
" w,h=display_mode[i].get_dim()\n",
" print w,\" by \",h"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Available display modes: \n",
"low : 640 by 480\n",
"medium : 800 by 600\n",
"high : 1600 by 1200\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.13, Page Number: 268<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class samp:\n",
" __a=None\n",
" def __init__(self,n):\n",
" self.__a=n\n",
" def get_a(self):\n",
" return self.__a\n",
"\n",
"#Initializing the list\n",
"sampArray=[samp(-1),samp(-2),samp(-3),samp(-4)]\n",
"\n",
"#Display\n",
"for i in range(4):\n",
" print sampArray[i].get_a(),' ',"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"-1 -2 -3 -4 \n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.14, Page Number: 269<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"class samp:\n",
" __a=None\n",
" __b=None\n",
" def __init__(self,n,m):\n",
" self.__a=n\n",
" self.__b=m\n",
" def get_a(self):\n",
" return self.__a\n",
" def get_b(self):\n",
" return self.__b\n",
" \n",
"#Initializing the list\n",
"sampArray=[[samp(1,2),samp(3,4)],\n",
" [samp(5,6),samp(7,8)],\n",
" [samp(9,10),samp(11,12)],\n",
" [samp(13,14),samp(15,16)]]\n",
"\n",
"#Display\n",
"for i in range(4):\n",
" print sampArray[i][0].get_a(),' ',\n",
" print sampArray[i][0].get_b()\n",
" print sampArray[i][1].get_a(),' ',\n",
" print sampArray[i][1].get_b()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"1 2\n",
"3 4\n",
"5 6\n",
"7 8\n",
"9 10\n",
"11 12\n",
"13 14\n",
"15 16\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.15, Page Number: 270<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"from ctypes import *\n",
"\n",
"class P_example(Structure):\n",
" __num=None\n",
" def set_num(self,val):\n",
" self.__num=val\n",
" def show_num(self):\n",
" print self.__num\n",
"\n",
"#Variable declaration\n",
"ob=P_example() #Declare an object to the structure\n",
"p=POINTER(P_example) #Declare a pointer to the structure\n",
"\n",
"ob.set_num(1) #access ob directly\n",
"ob.show_num()\n",
"\n",
"p=ob #assign p the address of ob\n",
"p.show_num() #access ob using pointer\n",
" \n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"1\n",
"1\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 11.16, Page Number: 271<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"class P_example(Structure):\n",
" __num=None\n",
" def set_num(self,val):\n",
" self.__num=val\n",
" def show_num(self):\n",
" print self.__num\n",
" \n",
"#Variable declaration\n",
"ob=[P_example(),P_example()] #Declare an object to the structure\n",
"p=POINTER(P_example) #Declare a pointer to the structure\n",
"\n",
"ob[0].set_num(10) #access objects directly\n",
"ob[1].set_num(20)\n",
"\n",
"p=ob #obtain pointer to first element\n",
"p[0].show_num() #access ob using pointer\n",
"\n",
"p[1].show_num()\n",
"\n",
"p[0].show_num()\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"10\n",
"20\n",
"10\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}