{
 "metadata": {
  "name": "",
  "signature": "sha256:be75d77e91d7005f064cd2c560347aec768e900f2e81ef47804d4b096bc083a6"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Chapter 7 : Pointers"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.1, Page No 157"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "x=5\n",
      "iPtr=id(x)\n",
      "iPtr=7"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.2, Page No 157"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "x=1\n",
      "iPtr=id(x)\n",
      "\n",
      "iPtr=5\n",
      "\n",
      "print \"\\n*iPtr = \"+str(iPtr)+\"\\n &x = \"+str(id(x))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "\n",
        "*iPtr = 5\n",
        " &x = 20176608\n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.3, Page No 158"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "x=5\n",
      "y=10\n",
      "iPtr=None\n",
      "\n",
      "print \"Pointer points to: \",iPtr\n",
      "iPtr=id(y)\n",
      "print \"Ptr now points to: \",iPtr\n",
      "x=iPtr\n",
      "print \"The value of x is now\",x\n",
      "iPtr=15\n",
      "print \"The value of y is now\",iPtr"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Pointer points to:  None\n",
        "Ptr now points to:  20373108\n",
        "The value of x is now 20373108\n",
        "The value of y is now 15\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.4, Page No 159"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def addTwoNumbers(x,y):\n",
      "    return x+y\n",
      "\n",
      "\n",
      "x=0\n",
      "y=0\n",
      "\n",
      "x=int(raw_input(\"Enter first number:\"))\n",
      "y=int(raw_input(\"Enter second number:\"))\n",
      "\n",
      "print \"Result is: \",addTwoNumbers(x,y)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Enter first number:10\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Enter second number:15\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Result is:  25\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.5, Page No 161"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def demoPassByValue(x):\n",
      "    x+=5\n",
      "    print \"The value of x is:\",x\n",
      "\n",
      "x=0\n",
      "x=int(raw_input(\"Enter a number:\"))\n",
      "demoPassByValue(x)\n",
      "print \"The original value of x did not change:\",x"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Enter a number:5\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The value of x is: 10\n",
        "The original value of x did not change: 5\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.6, Page No 162"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def demoPassByReference(x):\n",
      "    x+=5\n",
      "    print \"The value of x is now\",x\n",
      "\n",
      "x=0\n",
      "x=int(raw_input(\"Enter a number:\"))\n",
      "demoPassByReference(x)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Enter a number:10\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The value of x is now 15\n"
       ]
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.7, Page No 164"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "iArray=[1,2,3,4,5]\n",
      "iPtr=id(iArray)\n",
      "print \"Address of pointer: \",iPtr\n",
      "print \"First address of array: \",id(iArray[0])\n",
      "print \"Pointer points to: \",iArray[0]\n",
      "print \"First element of array contains\",iArray[0]"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Address of pointer:  28621960\n",
        "First address of array:  19652320\n",
        "Pointer points to:  1\n",
        "First element of array contains 1\n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.8, Page No 165"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def nameLength(name):\n",
      "    x=0\n",
      "    while(name[x] != '\\0'):\n",
      "        x+=1;\n",
      "    return x\n",
      "aName='\\0'\n",
      "aName=raw_input(\"Enter your first name: \")\n",
      "aName=aName+'\\0'\n",
      "print \"Your first name contains\"\n",
      "print str(nameLength(aName))+\" characters\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Enter your first name: mehta\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Your first name contains\n",
        "5 characters\n"
       ]
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.9, Page No 167"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def squareNumber(num):\n",
      "    for x in range(3):\n",
      "        num[x]=num[x]*num[x]\n",
      "\n",
      "iNumbers=[2,4,6]\n",
      "print \"The current array value are:\"\n",
      "\n",
      "for x in range(3):\n",
      "    print iNumbers[x]\n",
      "\n",
      "print \"\\n\"\n",
      "\n",
      "squareNumber(iNumbers)\n",
      "\n",
      "print \"The modified array values are :\"\n",
      "\n",
      "for x in range(3):\n",
      "    print iNumbers[x]\n",
      "\n",
      "print \"\\n\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "The current array value are:\n",
        "2\n",
        "4\n",
        "6\n",
        "\n",
        "\n",
        "The modified array values are :\n",
        "4\n",
        "16\n",
        "36\n",
        "\n",
        "\n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.10, Page No 168"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def printArgument(num):\n",
      "    print \"Read only argument is: \",num\n",
      "    \n",
      "iNumber=5\n",
      "printArgument(iNumber)\n",
      "    "
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Read only argument is:  5\n"
       ]
      }
     ],
     "prompt_number": 11
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.11, Page No 169"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def printArray(num):\n",
      "    for x in range(3):\n",
      "        print num[x]\n",
      "\n",
      "iNumbers=[2,4,6]\n",
      "printArray(iNumbers)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "2\n",
        "4\n",
        "6\n"
       ]
      }
     ],
     "prompt_number": 12
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.12, Page No 170"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def modifyArray(num):\n",
      "    for x in range(3):\n",
      "        num[x]=num[x]*num[x]\n",
      "        \n",
      "iNumbers=[2,4,6]\n",
      "modifyArray(iNumbers)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 14
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 7.13, Page No 173"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import random\n",
      "def encrypt(sMessage,random):\n",
      "    x=0\n",
      "    while(sMessage[x]):\n",
      "        sMessage+=str(random)\n",
      "        x+=1\n",
      "    x=0\n",
      "    print \"Encrypted message is: \"\n",
      "    \n",
      "    while(sMessage[x]):\n",
      "        print sMessage[x]\n",
      "        x+=1\n",
      "\n",
      "def decrypt(sMessage,random):\n",
      "    x=0\n",
      "    while(sMessage[x]):\n",
      "        sMessage[x]=sMessage[x]-str(random)\n",
      "        x+=1\n",
      "    x=0\n",
      "    while(sMessage[x]):\n",
      "        print sMessage[x]\n",
      "        x+=1\n",
      "        \n",
      "myString=range(21)\n",
      "iSelection=0\n",
      "iRand= (random.randint(1,4)%4)+1\n",
      "\n",
      "while(iSelection != 4):\n",
      "    print \"\\n\\n1\\t Encrypt Clear Text\\n\"\n",
      "    print \"2\\tDecrypt Cipher Text\\n\"\n",
      "    print \"3\\tGenerate New Key\\n\"\n",
      "    print \"4\\tQuit\\n\"\n",
      "    iSelection=int(raw_input(\"\\nSelect a Cryptography Option: \"))\n",
      "    \n",
      "    if(iSelection ==1):\n",
      "        myString=raw_input(\"\\nEnter one word as clear text to encrypt: \")\n",
      "        encrypt(myString,iRand)\n",
      "        break\n",
      "    elif(iSelection==2):\n",
      "        myString=raw_input(\"\\nEnter cipher text to decrypt: \")\n",
      "        decrypt(myString,iRand)\n",
      "        break\n",
      "    elif(iSelection==3):\n",
      "        iRand= (random.randrange(1,4,1)%4)+1\n",
      "        print \"\\nNew Key Generated\\n\"\n",
      "        break\n",
      "    else:\n",
      "            exit(0)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "\n",
        "\n",
        "1\t Encrypt Clear Text\n",
        "\n",
        "2\tDecrypt Cipher Text\n",
        "\n",
        "3\tGenerate New Key\n",
        "\n",
        "4\tQuit\n",
        "\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "\n",
        "Select a Cryptography Option: 1\n"
       ]
      },
      {
       "name": "stdout",
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "\n",
        "Enter one word as clear text to encrypt: bhavin\n"
       ]
      }
     ]
    }
   ],
   "metadata": {}
  }
 ]
}