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 "metadata": {
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  "signature": "sha256:619769e887714e6791182739416189f2f7fa6743af97af5b6710a3d8f08e8d46"
 },
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 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Chapter 4: Functions"
     ]
    },
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Example 4.1, page no. 103"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "def aax1():\n",
      "# code for function body \n",
      "    return (1.0)\n",
      "\n",
      "r = aax1();\n",
      "print r"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "1.0\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.2 & 4.3, page no. 106-108"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "This won't generate any output\n",
      "Examples 4.2 and 4.3 are same for python language.\n",
      "'''\n",
      "\n",
      "\n",
      "def pmax(a1,a2):\n",
      "    biggest = 0\n",
      "    if(a1 > a2):\n",
      "        biggest = a1\n",
      "    else:\n",
      "        biggest = a2\n",
      "\n",
      "#print \"larger of %d and %d is %d\\n\" %(a1, a2, biggest);\n",
      "\n",
      "\n",
      "\n",
      "for i in range(11):\n",
      "    for j in range(-10,11):\n",
      "       pmax(i,j)\n",
      "        \n",
      "# It shows that all variables scope is locally only. They can not be accessed from outside its scope.        "
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.4, page no. 109"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "def sq_root(x):\n",
      "    DELTA = 0.0001\n",
      "    curr_appx = 0\n",
      "    last_appx = 0\n",
      "    diff = 0\n",
      "    last_appx = x\n",
      "    diff = DELTA+1\n",
      "    while(diff > DELTA):\n",
      "        curr_appx = 0.5*(last_appx + x/last_appx)\n",
      "        diff = curr_appx - last_appx\n",
      "        if(diff < 0):\n",
      "            diff = -diff\n",
      "            last_appx = curr_appx\n",
      "    return(curr_appx)\n",
      " \n",
      "\n",
      "\n",
      "for i in range(1,101):\n",
      "    print \"root of %d is %f\\n\" %( i, sq_root(i))\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "root of 1 is 1.000000\n",
        "\n",
        "root of 2 is 1.414214\n",
        "\n",
        "root of 3 is 1.732051\n",
        "\n",
        "root of 4 is 2.000000\n",
        "\n",
        "root of 5 is 2.236068\n",
        "\n",
        "root of 6 is 2.449490\n",
        "\n",
        "root of 7 is 2.645751\n",
        "\n",
        "root of 8 is 2.828427\n",
        "\n",
        "root of 9 is 3.000000\n",
        "\n",
        "root of 10 is 3.162278\n",
        "\n",
        "root of 11 is 3.316625\n",
        "\n",
        "root of 12 is 3.464102\n",
        "\n",
        "root of 13 is 3.605551\n",
        "\n",
        "root of 14 is 3.741657\n",
        "\n",
        "root of 15 is 3.872983\n",
        "\n",
        "root of 16 is 4.000000\n",
        "\n",
        "root of 17 is 4.123106\n",
        "\n",
        "root of 18 is 4.242641\n",
        "\n",
        "root of 19 is 4.358899\n",
        "\n",
        "root of 20 is 4.472136\n",
        "\n",
        "root of 21 is 4.582576\n",
        "\n",
        "root of 22 is 4.690416\n",
        "\n",
        "root of 23 is 4.795832\n",
        "\n",
        "root of 24 is 4.898979\n",
        "\n",
        "root of 25 is 5.000000\n",
        "\n",
        "root of 26 is 5.099020\n",
        "\n",
        "root of 27 is 5.196152\n",
        "\n",
        "root of 28 is 5.291503\n",
        "\n",
        "root of 29 is 5.385165\n",
        "\n",
        "root of 30 is 5.477226\n",
        "\n",
        "root of 31 is 5.567764\n",
        "\n",
        "root of 32 is 5.656854\n",
        "\n",
        "root of 33 is 5.744563\n",
        "\n",
        "root of 34 is 5.830952\n",
        "\n",
        "root of 35 is 5.916080\n",
        "\n",
        "root of 36 is 6.000000\n",
        "\n",
        "root of 37 is 6.082763\n",
        "\n",
        "root of 38 is 6.164414\n",
        "\n",
        "root of 39 is 6.244998\n",
        "\n",
        "root of 40 is 6.324555\n",
        "\n",
        "root of 41 is 6.403124\n",
        "\n",
        "root of 42 is 6.480741\n",
        "\n",
        "root of 43 is 6.557439\n",
        "\n",
        "root of 44 is 6.633250\n",
        "\n",
        "root of 45 is 6.708204\n",
        "\n",
        "root of 46 is 6.782330\n",
        "\n",
        "root of 47 is 6.855655\n",
        "\n",
        "root of 48 is 6.928203\n",
        "\n",
        "root of 49 is 7.000000\n",
        "\n",
        "root of 50 is 7.071068\n",
        "\n",
        "root of 51 is 7.141428\n",
        "\n",
        "root of 52 is 7.211103\n",
        "\n",
        "root of 53 is 7.280110\n",
        "\n",
        "root of 54 is 7.348469\n",
        "\n",
        "root of 55 is 7.416198\n",
        "\n",
        "root of 56 is 7.483315\n",
        "\n",
        "root of 57 is 7.549834\n",
        "\n",
        "root of 58 is 7.615773\n",
        "\n",
        "root of 59 is 7.681146\n",
        "\n",
        "root of 60 is 7.745967\n",
        "\n",
        "root of 61 is 7.810250\n",
        "\n",
        "root of 62 is 7.874008\n",
        "\n",
        "root of 63 is 7.937254\n",
        "\n",
        "root of 64 is 8.000000\n",
        "\n",
        "root of 65 is 8.062258\n",
        "\n",
        "root of 66 is 8.124038\n",
        "\n",
        "root of 67 is 8.185353\n",
        "\n",
        "root of 68 is 8.246211\n",
        "\n",
        "root of 69 is 8.306624\n",
        "\n",
        "root of 70 is 8.366600\n",
        "\n",
        "root of 71 is 8.426150\n",
        "\n",
        "root of 72 is 8.485281\n",
        "\n",
        "root of 73 is 8.544004\n",
        "\n",
        "root of 74 is 8.602325\n",
        "\n",
        "root of 75 is 8.660254\n",
        "\n",
        "root of 76 is 8.717798\n",
        "\n",
        "root of 77 is 8.774964\n",
        "\n",
        "root of 78 is 8.831761\n",
        "\n",
        "root of 79 is 8.888194\n",
        "\n",
        "root of 80 is 8.944272\n",
        "\n",
        "root of 81 is 9.000000\n",
        "\n",
        "root of 82 is 9.055385\n",
        "\n",
        "root of 83 is 9.110434\n",
        "\n",
        "root of 84 is 9.165151\n",
        "\n",
        "root of 85 is 9.219544\n",
        "\n",
        "root of 86 is 9.273618\n",
        "\n",
        "root of 87 is 9.327379\n",
        "\n",
        "root of 88 is 9.380832\n",
        "\n",
        "root of 89 is 9.433981\n",
        "\n",
        "root of 90 is 9.486833\n",
        "\n",
        "root of 91 is 9.539392\n",
        "\n",
        "root of 92 is 9.591663\n",
        "\n",
        "root of 93 is 9.643651\n",
        "\n",
        "root of 94 is 9.695360\n",
        "\n",
        "root of 95 is 9.746794\n",
        "\n",
        "root of 96 is 9.797959\n",
        "\n",
        "root of 97 is 9.848858\n",
        "\n",
        "root of 98 is 9.899495\n",
        "\n",
        "root of 99 is 9.949874\n",
        "\n",
        "root of 100 is 10.000000\n",
        "\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.6, page no. 115"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "\n",
      "def called_func(a,b):\n",
      "    temp = a * b\n",
      "    print temp\n",
      "\n",
      "called_func(1,2*3.5)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "7.0\n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.7, page no. 116"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "\n",
      "def changer(x):\n",
      "    while(x!=0):\n",
      "        print \"changer: x=%d\\n\" %(x)\n",
      "        x-=1\n",
      "\n",
      "i = 5\n",
      "print \"before i=%d\\n\" %( i);\n",
      "changer(i);\n",
      "print \"after i=%d\\n\" %( i);"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "before i=5\n",
        "\n",
        "changer: x=5\n",
        "\n",
        "changer: x=4\n",
        "\n",
        "changer: x=3\n",
        "\n",
        "changer: x=2\n",
        "\n",
        "changer: x=1\n",
        "\n",
        "after i=5\n",
        "\n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.8, page no. 120"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "Do not try to run....\n",
      "It's infinite looping program..\n",
      "\n",
      "This program shows how a function calls itself.\n",
      "'''\n",
      "\n",
      "def expr():\n",
      "    val = 0\n",
      "    ch_in = 0\n",
      "    val = mul_exp()\n",
      "    while True:\n",
      "        ch_in = raw_input(\"Enter + or - \")\n",
      "        if ch_in =='+':\n",
      "            val = val + mul_exp();\n",
      "        else:\n",
      "            if ch_in == '-':\n",
      "                val = val - mul_exp()\n",
      "            else:\n",
      "                return val\n",
      "\n",
      "    return val\n",
      "\n",
      "def mul_exp():\n",
      "    val = 0\n",
      "    ch_in = 0\n",
      "    val = unary_exp()\n",
      "    while True:\n",
      "        ch_in = raw_input(\"Enter * or / or % \")\n",
      "        if ch_in =='*':\n",
      "            val = val * unary_exp();\n",
      "        else:\n",
      "            if ch_in == '/':\n",
      "                val = val - mul_exp()\n",
      "            else:\n",
      "                if ch_in =='%':\n",
      "                    val = val % unary_exp()\n",
      "                else:\n",
      "                    return val\n",
      "    return val\n",
      "\n",
      "def unary_exp():\n",
      "    val=0\n",
      "    ch_in = raw_input(\"Enter + or - \")\n",
      "    if ch_in =='+':\n",
      "        val = unary_exp()\n",
      "    else:\n",
      "        if ch_in == '-':\n",
      "            val = -unary_exp()\n",
      "        else:\n",
      "            val = primary()\n",
      "            return val\n",
      "\n",
      "    return val\n",
      "\n",
      "def primary():\n",
      "    val = 0\n",
      "    ch_in = raw_input('Enter value')\n",
      "    if (ch_in >= '0' and ch_in <= '9'):\n",
      "        val = ch_in - '0'\n",
      "        return val\n",
      "    if ch_in == '(':\n",
      "        val = expr()\n",
      "    print \"error: primary read %d\\n\" %ch_in\n",
      "    return val\n",
      "\n",
      "\n",
      "val = 0\n",
      "while True:\n",
      "    print \"expression: \"\n",
      "    val = expr();\n",
      "    if(raw_input()!= '\\n'):\n",
      "        print \"error\\n\"\n",
      "        while(raw_input() != '\\n'):\n",
      "            pass\n",
      "        \n",
      "    else:\n",
      "        print \"result is %d\\n\" %val"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.9, page no. 123"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#No output will be produced\n",
      "\n",
      "from second import * #importing all content of second.py file\n",
      "\n",
      "\n",
      "i=0\n",
      "print f_in_other_place(i) # declaration "
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.10, page no. 124"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "Example 4.10\n",
      "/* example library module */\n",
      "/* only 'callable' is visible outside */\n",
      "'''\n",
      "\n",
      "\n",
      "__buf=[]\n",
      "__length = 0\n",
      "\n",
      "def __fillup__():\n",
      "    while (length <100):\n",
      "        buf[length] = 0\n",
      "                length += 1\n",
      "\n",
      "def callable ():\n",
      "    if (length ==0):\n",
      "        fillup ()\n",
      "                a = buf[length]\n",
      "                length-=1\n",
      "        return (a)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.11, page no. 126"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "python doesn't have static variable \n",
      "we can use global variable for counting \n",
      "this demonstrates how it works...\n",
      "'''\n",
      "\n",
      "count = 0\n",
      "\n",
      "def small_val ():\n",
      "    count+=1\n",
      "    return (count % 16)\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "Example 4.12, page no. 126"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "'''\n",
      "Example 4.12\n",
      "python doesn't have static variables.\n",
      "'''\n",
      "\n",
      "\n",
      "depth=0\n",
      "def  r_func():\n",
      "    depth+=1\n",
      "    if (depth > 200):\n",
      "        print (\"excessive recursion\\n\")\n",
      "        sys.exit(0)\t\n",
      "    else:\n",
      "        '''/* do usual thing,\n",
      "        * not shown here.\n",
      "        * This last action\n",
      "        * occasionally results in another\n",
      "        * call on r_func()\n",
      "        */\n",
      "        '''\n",
      "        x_func()\n",
      "\n",
      "    depth-=1"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    }
   ],
   "metadata": {}
  }
 ]
}