path: root/C++_from_the_Ground/Chapter_18(1).ipynb

{
 "metadata": {
  "name": "Chapter 18"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h1>Chapter 18: The C++ I/O System<h1>"
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.1, Page Number: 421<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implementation of overloading << for print in python'''\n\nclass three_d:\n    def __init__(self,a,b,c):   #3D coordinates\n        self.x=a\n        self.y=b\n        self.z=c\n    #Display x,y,z coordinates - three_d inserter.\n    def __repr__(self):\n        return str(self.x)+\", \"+str(self.y)+\", \"+str(self.z)+\"\\n\"\n\n#Variable declaration\na=three_d(1,2,3)\nb=three_d(3,4,5)\nc=three_d(5,6,7)\n\n#Result\nprint a,b,c",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "1, 2, 3\n 3, 4, 5\n 5, 6, 7\n\n"
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.2, Page Number: 423<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Using a friend function implement overloading of << in python'''\n\nclass thrnee_d:\n    def __init__(self,a,b,c):   #3D coordinates\n        self.x=a\n        self.y=b\n        self.z=c\n    #Display x,y,z coordinates - three_d inserter.\n    __repr__=repr                              \n       \n#Friend function        \ndef repr():\n    return str(self.x)+\", \"+str(self.y)+\", \"+str(self.z)+\"\\n\"\n\n#Variable declaration\na=three_d(1,2,3)\nb=three_d(3,4,5)\nc=three_d(5,6,7)\n\nprint a,b,c",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "1, 2, 3\n 3, 4, 5\n 5, 6, 7\n\n"
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.3, Page Number: 424<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implementation of overloading << and >> in python'''\n\nclass three_d:\n    def __init__(self,a,b,c):   #3D coordinates\n        self.x=a\n        self.y=b\n        self.z=c\n    #Display x,y,z coordinates - three_d inserter.\n    def __repr__(self):\n        return str(self.x)+\", \"+str(self.y)+\", \"+str(self.z)\n\n#Variable declaration\na=three_d(1,2,3)\n\nprint a\n\n#User input\nprint \"Enter X,Y,Z values:\"\na=three_d(4,5,6)   \nprint a",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "1, 2, 3\nEnter X,Y,Z values:\n4, 5, 6\n"
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.4, Page Number: 428<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implementing some ios flags in python'''\n\n\nprint '{0:+d}'.format(123),   #for ios::showpos\nif(123.23>0):\n    i='{0:e}'.format(123.23)  #for ios::scientific  \n    i='+'+i\n    print i\nelse :\n    print '{0:e}'.format(123.23)\n   ",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "+123 +1.232300e+02\n"
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.5, Page Number: 430<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implementing some ios flags in python'''\n\nimport string\n\nprint '{0:+d}'.format(123),        #for ios::showpos\nif(123.23>0):\n    i='{0:e}'.format(123.23)       #for ios::scientific  \n    i='+'+i\n    print i\nelse :\n    print '{0:e}'.format(123.23)\n\n    \nprint '{:10.2f}'.format(123.23),   #2 digits left of decimal\nif(123.23>0):\n    i='{0:.2e}'.format(123.23)     #for ios::scientific  \n    i='+'+i\n    print i\nelse :\n    print '{0:.2e}'.format(123.23)\n    \n    \nprint '{:#>10}'.format(str(123)),  #for ios::fill\nif(123.23>0):                      \n    i='{0:.2e}'.format(123.23)  #for ios::scientific  \n    i='+'+i\n    print i\nelse :\n    print '{0:.2e}'.format(123.23)\n\n",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "+123 +1.232300e+02\n    123.23 +1.23e+02\n#######123 +1.23e+02\n"
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.6, Page Number: 432<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implement io manipulators in python'''\n\nprint '{0:.0e}'.format(1000.243)        #for setprecision\nprint '{:>20}'.format(\"Hello There\")    #to set width and right align\n",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "1e+03\n         Hello There\n"
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.7, Page Number: 433<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implementing some ios flags in python'''\n\nprint '{0:+d}'.format(123),   #for ios::showpos\nif(123.23>0):\n    i='{0:e}'.format(123.23)  #for ios::scientific  \n    i='+'+i\n    print i\nelse :\n    print '{0:e}'.format(123.23)\n   ",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "+123 +1.232300e+02\n"
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.8, Page Number: 433<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Removing leading whitespaces from a string'''\n\n#User input\ns=\"   Hello\"\n\n#Result\nprint s.lstrip()    #lstrip removes leading spaces",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Hello\n"
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.9, Page Number: 434<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implementing some ios flags in python'''\n\ndef setup(s):\n    return '{:$<10}'.format(str(s))\n\n\n#Result\nprint 10,setup(10)\n\n\n",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "10 10$$$$$$$$\n"
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.10, Page Number: 435<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Prompting the user to enter number in hexadecimal form'''\n\ndef prompt():\n    print \"Enter number using hex format:\"\n    hex=0x46\n    return hex\n\n\n#Result\ni=prompt()\nprint i\n\n",
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.11, Page Number: 438<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Program to write to a file'''\n\n#Open a file, creating one if it does not already exist\nout=open(\"test\",'w')\n\n#In case file cannot open\nif(not(out)):\n    print \"Cannot open file.\"\nelse:\n    #Write to file\n    out.write(\"10 123.23\\n\")\n    out.write(\"This is a short text file.\")\n    #Close the file\n    out.close()",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 8
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.12, Page Number: 438<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Program to read to a file'''\n\n#Open a file, creating one if it does not already exist\nIn=open(\"test\",'r')\n\n#In case file cannot open\nif(not(In)):\n    print \"Cannot open file.\"\nelse:\n    #Read file\n    i=In.read(2)\n    ch=In.read(1)\n    f=In.read(6)\n    str=In.read()\n    print i,f,ch\n    print str\n    #Close the file\n    out.close()",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "10 123.23  \n\nThis is a short text file.\n"
      }
     ],
     "prompt_number": 9
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.13, Page Number: 439<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Program to read to a file provided on the screen'''\n#Program cannot be provided here, so error is obtained\n\nimport sys\n                                     \nif not(len(sys.argv)==2):\n    print \"Usage: PR <filename>\\n\"\nelse:\n    #Open a file\n    In=open(sys.argv[1],'r')\n\n    #In case file cannot open\n    if(not(In)):\n        print \"Cannot open file.\"\n    else:\n        #Read file\n        ch=In.read()\n        print ch\n        In.close()\n    \n",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Usage: PR <filename>\n\n"
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.14, Page Number: 440<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Program to write to a file'''\n\nimport sys\n\np=\"hello there\"\n\nout=open(\"test\",'w')\n\n#In case file cannot open\nif(not(out)):\n    print \"Cannot open file.\"\nelse:\n    #Write to file\n    for i in range(len(p)):\n        out.write(p[i])\n",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 11
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.15, Page Number: 441<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Program to read and write in a file'''\n\nimport sys\n\nn=[1,2,3,4,5]\n\n#Open a file 'test'\nout=open(\"test\",'w')\n\n#In case file cannot open\nif(not(out)):\n    print \"Cannot open file.\"\nelse:\n    #Write to file\n    for i in range(5):\n        out.write(chr(n[i]))\n    out.close()\n    \nfor i in range(5):         #clear array\n    n[i]=0\n    \n#Open the file\nIn=open(\"test\",'r')\n\n#In case file cannot open\nif(not(In)):\n    print \"Cannot open file.\"\nelse:\n    #Read file\n    for i in range(5):\n        n[i]=ord(In.read(1))\n\n#Result, shows value from file\nfor i in range(5):\n    print n[i],\n    \nIn.close()",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "1 2 3 4 5\n"
      }
     ],
     "prompt_number": 12
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.16, Page Number: 442<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Detect end-of-file for a file on the screen'''\n#File cannot be provided here, so program wont work\nimport sys\n                                     \nif not(len(sys.argv)==2):\n    print \"Usage: PR <filename>\\n\"\nelse:\n    #Open a file\n    In=open(sys.argv[1],'r')\n\n    #In case file cannot open\n    if(not(In)):\n        print \"Cannot open file.\"\n    else:\n        #Read file\n        while True:\n            ch=In.read(1)\n            if not ch:\n                break\n            print ch,\n    #Close file\n    In.close()\n                ",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Usage: PR <filename>\n\n"
      }
     ],
     "prompt_number": 13
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.17, Page Number: 443<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Program to compare files'''\n\n#Since file names cannot be provided, two \n#files are being created test1 and test2\n\n#creating test1\nout=open(\"test1\",'w')\nout.write(\"Hello\")\nout.close()\n\n#creating test2\nout=open(\"test2\",'w')\nout.write(\"There\")\nout.close()\n\n\n#Open test1\nf1=open(\"test1\",'r')\n#In case file cannot open\nif(not(In)):\n    print \"Cannot open file.\"\n\n#Open test2\nf2=open(\"test2\",'r')\n#In case file cannot open\nif(not(In)):\n    print \"Cannot open file.\"\n    \nprint \"Comparing files...\"\n\nbuf1=f1.read()\nbuf2=f2.read()\nprint buf1,buf2\n\nif len(buf1)==len(buf2):\n    print \"Files are of different sizes.\"\n    f1.close()\n    f2.close()\nelse:\n    #compare contents of buffers\n    flag=1\n    for i in range(len(buf1)):\n        if not(buf1[i]==buf2[i]):\n            print \"Files differ.\"\n            f1.close()\n            f2.close()\n            flag=0\n            break\n    if flag==1:\n        print \"Files are the same.\"\n        \n        ",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Comparing files...\nHello There\nFiles are of different sizes.\n"
      }
     ],
     "prompt_number": 14
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.18, Page Number: 445<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Read a string and print it'''\n\nprint \"Enter your name:\"\n\n#User imput\nstr=\"hello world\"\n\nprint str",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "Enter your name:\nhello world\n"
      }
     ],
     "prompt_number": 15
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.19, Page Number: 447<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Demonstrate random access by writing X at a specified location'''\n\n#Since arguments cannot be provided file test  \n#is created and X is written in the 3nd location.\n\n#Open test\nout=open(\"test\",'r+b')\nout.write(\"Hello\")\n\n\n#In case file cannot open\nif(not(out)):\n    print \"Cannot open file.\"\nelse:\n    out.seek(2,0)\n    out.write('X')\n    out.close()\n    \n",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.20, Page Number: 447<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Display a file from a given point'''\n\n#Here, file is displayed from 3nd position\n\n#Open test\nout=open(\"test\",'r+b')\nout.write(\"Hello\")\nout.close()\n\nIn=open(\"test\",'r')\n#In case file cannot open\nif(not(In)):\n    print \"Cannot open file.\"\nelse:\n    In.seek(2,0)\n    ch=In.read()\n    print ch\n    \n",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "llo\n"
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": "<h3>Example 18.21, Page Number: 450<h3>"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "'''Implement use of overloaded inserter to write three_d'''\n\nclass three_d:\n    def __init__(self,a,b,c):\n        self.__x=a\n        self.__y=b\n        self.__z=c\n    def __repr__(self):\n        c=(\"%d\"%self.__x)+\", \"+(\"%d\"%self.__y)+\", \"+(\"%d\"%self.__z)+\"\\n\"\n        return c \n\n#Variable declaration\na=three_d(1,2,3)\nb=three_d(3,4,5)\nc=three_d(5,6,7)\n\n#Open threed\nout=open(\"threed\",'w')\n#In case file cannot open\nif(not(out)):\n    print \"Cannot open file.\"\nelse:\n    out.write(a.__repr__())\n    out.write(b.__repr__())\n    out.write(c.__repr__())\n\n    ",
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 18
    },
    {
     "cell_type": "raw",
     "metadata": {},
     "source": ""
    }
   ],
   "metadata": {}
  }
 ]
}