{ "metadata": { "name": "", "signature": "sha256:3dbb4b61b32533eb72607c7c790e9f8f91b9c2e123ddbd5190ffe13a1b2b7647" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "

Chapter 18: The C++ I/O System

" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.1, Page Number: 421

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "class 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\n", "a=three_d(1,2,3)\n", "b=three_d(3,4,5)\n", "c=three_d(5,6,7)\n", "\n", "#Result\n", "print 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": [ "

Example 18.2, Page Number: 423

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "class 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 \n", "def repr():\n", " return str(self.x)+\", \"+str(self.y)+\", \"+str(self.z)+\"\\n\"\n", "\n", "#Variable declaration\n", "a=three_d(1,2,3)\n", "b=three_d(3,4,5)\n", "c=three_d(5,6,7)\n", "\n", "print 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": [ "

Example 18.3, Page Number: 424

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "class 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\n", "a=three_d(1,2,3)\n", "\n", "print a\n", "\n", "#User input\n", "print \"Enter X,Y,Z values:\"\n", "a=three_d(4,5,6) \n", "print a" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "1, 2, 3\n", "Enter X,Y,Z values:\n", "4, 5, 6\n" ] } ], "prompt_number": 3 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.4, Page Number: 428

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "print '{0:+d}'.format(123), #for ios::showpos\n", "if(123.23>0):\n", " i='{0:e}'.format(123.23) #for ios::scientific \n", " i='+'+i\n", " print i\n", "else :\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": [ "

Example 18.5, Page Number: 430

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import string\n", "\n", "print '{0:+d}'.format(123), #for ios::showpos\n", "if(123.23>0):\n", " i='{0:e}'.format(123.23) #for ios::scientific \n", " i='+'+i\n", " print i\n", "else :\n", " print '{0:e}'.format(123.23)\n", "\n", " \n", "print '{:10.2f}'.format(123.23), #2 digits left of decimal\n", "if(123.23>0):\n", " i='{0:.2e}'.format(123.23) #for ios::scientific \n", " i='+'+i\n", " print i\n", "else :\n", " print '{0:.2e}'.format(123.23)\n", " \n", " \n", "print '{:#>10}'.format(str(123)), #for ios::fill\n", "if(123.23>0): \n", " i='{0:.2e}'.format(123.23) #for ios::scientific \n", " i='+'+i\n", " print i\n", "else :\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": [ "

Example 18.6, Page Number: 432

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "print '{0:.0e}'.format(1000.243) #for setprecision\n", "print '{:>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": [ "

Example 18.7, Page Number: 433

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "print '{0:+d}'.format(123), #for ios::showpos\n", "if(123.23>0):\n", " i='{0:e}'.format(123.23) #for ios::scientific \n", " i='+'+i\n", " print i\n", "else :\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": [ "

Example 18.8, Page Number: 433

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#User input\n", "s=\" Hello\"\n", "\n", "#Result\n", "print 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": [ "

Example 18.9, Page Number: 434

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "def setup(s):\n", " return '{:$<10}'.format(str(s))\n", "\n", "\n", "#Result\n", "print 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": [ "

Example 18.10, Page Number: 435

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "def prompt():\n", " print \"Enter number using hex format:\"\n", " hex=0x46\n", " return hex\n", "\n", "\n", "#Result\n", "i=prompt()\n", "print i\n", "\n" ], "language": "python", "metadata": {}, "outputs": [] }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.11, Page Number: 438

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Open a file, creating one if it does not already exist\n", "out=open(\"test\",'w')\n", "\n", "#In case file cannot open\n", "if(not(out)):\n", " print \"Cannot open file.\"\n", "else:\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": [ "

Example 18.12, Page Number: 438

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Open a file, creating one if it does not already exist\n", "In=open(\"test\",'r')\n", "\n", "#In case file cannot open\n", "if(not(In)):\n", " print \"Cannot open file.\"\n", "else:\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", "\n", "This is a short text file.\n" ] } ], "prompt_number": 9 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.13, Page Number: 439

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import sys\n", " \n", "if not(len(sys.argv)==2):\n", " print \"Usage: PR \\n\"\n", "else:\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 \n", "\n" ] } ], "prompt_number": 10 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.14, Page Number: 440

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import sys\n", "\n", "p=\"hello there\"\n", "\n", "out=open(\"test\",'w')\n", "\n", "#In case file cannot open\n", "if(not(out)):\n", " print \"Cannot open file.\"\n", "else:\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": [ "

Example 18.15, Page Number: 441

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import sys\n", "\n", "n=[1,2,3,4,5]\n", "\n", "#Open a file 'test'\n", "out=open(\"test\",'w')\n", "\n", "#In case file cannot open\n", "if(not(out)):\n", " print \"Cannot open file.\"\n", "else:\n", " #Write to file\n", " for i in range(5):\n", " out.write(chr(n[i]))\n", " out.close()\n", " \n", "for i in range(5): #clear array\n", " n[i]=0\n", " \n", "#Open the file\n", "In=open(\"test\",'r')\n", "\n", "#In case file cannot open\n", "if(not(In)):\n", " print \"Cannot open file.\"\n", "else:\n", " #Read file\n", " for i in range(5):\n", " n[i]=ord(In.read(1))\n", "\n", "#Result, shows value from file\n", "for i in range(5):\n", " print n[i],\n", " \n", "In.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": [ "

Example 18.16, Page Number: 442

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import sys\n", " \n", "if not(len(sys.argv)==2):\n", " print \"Usage: PR \\n\"\n", "else:\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 \n", "\n" ] } ], "prompt_number": 13 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.17, Page Number: 443

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#creating test1\n", "out=open(\"test1\",'w')\n", "out.write(\"Hello\")\n", "out.close()\n", "\n", "#creating test2\n", "out=open(\"test2\",'w')\n", "out.write(\"There\")\n", "out.close()\n", "\n", "\n", "#Open test1\n", "f1=open(\"test1\",'r')\n", "#In case file cannot open\n", "if(not(In)):\n", " print \"Cannot open file.\"\n", "\n", "#Open test2\n", "f2=open(\"test2\",'r')\n", "#In case file cannot open\n", "if(not(In)):\n", " print \"Cannot open file.\"\n", " \n", "print \"Comparing files...\"\n", "\n", "buf1=f1.read()\n", "buf2=f2.read()\n", "print buf1,buf2\n", "\n", "if len(buf1)==len(buf2):\n", " print \"Files are of different sizes.\"\n", " f1.close()\n", " f2.close()\n", "else:\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...\n", "Hello There\n", "Files are of different sizes.\n" ] } ], "prompt_number": 14 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.18, Page Number: 445

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "print \"Enter your name:\"\n", "\n", "#User imput\n", "str=\"hello world\"\n", "\n", "print str" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Enter your name:\n", "hello world\n" ] } ], "prompt_number": 15 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 18.19, Page Number: 447

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Open test\n", "out=open(\"test\",'r+b')\n", "out.write(\"Hello\")\n", "\n", "\n", "#In case file cannot open\n", "if(not(out)):\n", " print \"Cannot open file.\"\n", "else:\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": [ "

Example 18.20, Page Number: 447

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Open test\n", "out=open(\"test\",'r+b')\n", "out.write(\"Hello\")\n", "out.close()\n", "\n", "In=open(\"test\",'r')\n", "#In case file cannot open\n", "if(not(In)):\n", " print \"Cannot open file.\"\n", "else:\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": [ "

Example 18.21, Page Number: 450

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "class 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\n", "a=three_d(1,2,3)\n", "b=three_d(3,4,5)\n", "c=three_d(5,6,7)\n", "\n", "#Open threed\n", "out=open(\"threed\",'w')\n", "#In case file cannot open\n", "if(not(out)):\n", " print \"Cannot open file.\"\n", "else:\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": {} } ] }