{
 "metadata": {
  "name": "Chapter 13"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": "Chapter 13: Simple pointers"
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.1, Page number: 225"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.1.py\n# To print the value of 'thing_var' and 'thing_ptr'\n\n\n# Variable declaration\nthing_var = 2\n\n# Calculation and result\nprint ('Thing %d' % thing_var)\n\nthing_ptr = thing_var\nthing_ptr = 3\nprint ('Thing %d' % thing_ptr)",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Thing 2\nThing 3\n"
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.2, Page number: 227"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.2.py\n# To loop through the value of 'count' from 1 to 10\n\n\n# Function declaration\ndef inc_count (count_ptr) :\n   count_ptr += 1\n   return count_ptr\n\n# Calculation and result\ncount = 0\n\nwhile (count < 10) :\n   print ('Count %d\\n' % inc_count (count))\n   count += 1",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Count 1\n\nCount 2\n\nCount 3\n\nCount 4\n\nCount 5\n\nCount 6\n\nCount 7\n\nCount 8\n\nCount 9\n\nCount 10\n\n"
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.3, Page number: 230"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.3.py\n# To print the addresses and elements of a character array\n\n\n# Variable declaration\narray = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']\n\n# Calculation and result\nprint ('&array[index] (array+index) array[index]\\n')\n\nfor index in range (0, 10) :\n   print ('0x%s 0x%s 0x%s\\n' % (id (array[index]), id (array[index]), array[index]))",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "&array[index] (array+index) array[index]\n\n0x20916008 0x20916008 0x0\n\n0x20270280 0x20270280 0x1\n\n0x20733728 0x20733728 0x2\n\n0x20916464 0x20916464 0x3\n\n0x20270232 0x20270232 0x4\n\n0x20733560 0x20733560 0x5\n\n0x20270256 0x20270256 0x6\n\n0x20733752 0x20733752 0x7\n\n0x20916512 0x20916512 0x8\n\n0x20916032 0x20916032 0x9\n\n"
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.4, Page number: 232"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.4.py\n# To count the number of elements before zero in an array\n\n\n# Variable declaration\narray = [4, 5, 8, 9, 8, 1, 0, 1, 9, 3]\nindex = 0\n\n# Calculation and result\nwhile (array[index] != 0) :\n   index += 1\n\nprint ('Number of elements before zero %d\\n' % index)",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Number of elements before zero 6\n\n"
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.5, Page number: 232"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.5.py\n# To count the number of elements before zero in an array\n\n\n# Variable declaration\narray = [4, 5, 8, 9, 8, 1, 0, 1, 9, 3]\nindex = 0\n\n# Calculation and result\nwhile (array[index] != 0) :\n   index += 1\n\nprint ('Number of elements before zero %d\\n' % index)",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Number of elements before zero 6\n\n"
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.6, Page number: 233"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.6.py\n# To initialize the elements of an array to 0\n\n\n# Variable declaration\ndata = []\n\n# Calculation and result\nfor index in range (0, 10) :\n   data.append(0)\nprint (data)",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]\n"
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.10, Page number: 238"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.10.py\n# To split a string of the form 'First/Last' into two strings\n\n\n# Variable declaration\nline = 'Steve/Oualline'\n\n# Calculation and result\nfirst_ptr, last_ptr = line.split('/')\nprint ('First: %s Last: %s\\n' % (first_ptr, last_ptr))",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "First: Steve Last: Oualline\n\n"
      }
     ],
     "prompt_number": 8
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.11, Page number: 240"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.11.py\n# To return a temporary filename\n\n\n# Function declaration\ndef tmp_name() :\n   if not hasattr (tmp_name, 'sequence') :\n      tmp_name.sequence = 0\n   tmp_name.sequence += 1\n   name = 'tmp'\n   name += str (tmp_name.sequence)\n   return name\n\n# Calculation and result\nprint ('Name: %s\\n' % tmp_name())",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Name: tmp1\n\n"
      }
     ],
     "prompt_number": 9
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.12, Page number: 245"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.12.py\n# To format files for printing\n\n\n# Variable and function declaration\nimport sys\nv_count = sys.argv\ncounter = len(sys.argv)\n\n# Produces verbose messages\nverbose = 0\n\n# Sends output to a file\nout_file = open ('print.out', 'w')\n\n# Sets the number of lines per page\nline_max = 66\n\ndef do_file (name) :\n   print ('Verbose %d Lines %d Input %s Output %s\\n' % (verbose, line_max, name, out_file.name))\n\ndef usage() :\n   print ('Usage is %s [options] [file-list]\\n' % program_name)\n   print ('Options\\n')\n   print (' -v verbose\\n')\n   print (' -l<number> Number of lines\\n')\n   print (' -o<name> Set output filename\\n')\n   sys.exit(1)\n   \n# Calculation and result\nprogram_name = str (sys.argv[0])\n\nwhile ((counter > 1) and (sys.argv[1][0] == '-')) :\n   if (sys.argv[1][1] == 'v') :\n      verbose = 1\n      break\n\n   elif (sys.argv[1][1] == 'o') :\n      temp = str (sys.argv[1])\n      out_file.write (temp)\n      break\n\n   elif (sys.argv[1][1] == 'l') :\n      line_max = int (sys.argv[1][2])\n      break\n\n   else :\n      print ('Bad option %s\\n' % sys.argv[1])\n      usage()\n\n   for index in range (0, counter) :\n      if (index == counter - 1) :\n         break\n      else :\n         v_count[index] = v_count[index + 1]\n\n   counter -= 1\n\nif (counter == 1) :\n   do_file ('print.in')\n\nelse :\n   while (counter > 1) :\n      do_file (sys.argv[1])\n\n      for index in range (0, counter) :\n         if (index == counter - 1) :\n            break\n         else :\n            v_count[index] = v_count[index + 1]\n         \n      counter -= 1\n\nout_file.close()",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "ename": "SystemExit",
       "evalue": "1",
       "output_type": "pyerr",
       "traceback": [
        "An exception has occurred, use %tb to see the full traceback.\n",
        "\u001b[1;31mSystemExit\u001b[0m\u001b[1;31m:\u001b[0m 1\n"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Bad option -f\n\nUsage is -c [options] [file-list]\n\nOptions\n\n -v verbose\n\n -l<number> Number of lines\n\n -o<name> Set output filename\n\n"
      },
      {
       "output_type": "stream",
       "stream": "stderr",
       "text": "To exit: use 'exit', 'quit', or Ctrl-D."
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "heading",
     "level": 3,
     "metadata": {},
     "source": "Example 13.13, Page number: 248"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "# Example 13.13.py\n# To return a new temporary filename\n\n\n# Function declaration\ndef tmp_name() :\n   if not hasattr (tmp_name, 'sequence') :\n      tmp_name.sequence = 0\n   tmp_name.sequence += 1\n   name = 'tmp'\n   name += str (tmp_name.sequence)\n   return name\n\n# Calculation and result\nname1 = tmp_name()\nname2 = tmp_name()\nprint ('Name1: %s\\n' % name1)\nprint ('Name2: %s\\n' % name2)",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Name1: tmp1\n\nName2: tmp2\n\n"
      }
     ],
     "prompt_number": 11
    }
   ],
   "metadata": {}
  }
 ]
}