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{
"metadata": {
"name": "Chapter 10"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": "<h1>Chapter 10: Structures and Unions<h1>"
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.1, Page Number: 223<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''A simple inventory prohram that uses an array of structures/ '''\n'''Implementing structures in python'''\n\n\nclass inv_type:\n def __init__(self):\n self.item=None\n self.cost=0\n self.retail=0\n self.on_hand=0\n self.lead_time=0\n\n#Variable declaration\nsize=100 \ninvtry = []*size\ni=5 #User iput for menu selection\n\n#Initialize the array\ndef init_list():\n for t in range(size):\n invtry.append(inv_type())\n \n#get a menu selection\ndef menu():\n global i\n print \"(E)nter\"\n print \"(D)isplay\"\n print \"(U)pdate\"\n print \"(Q)uit\"\n print \"choose one: \"\n i-=1\n return i\n\n#enter items into the list\ndef enter():\n #find the first free structure\n for i in range(size):\n if not(invtry[i].item==None):\n break\n #i will be size if list is full\n if i==size:\n print \"List full.\"\n return\n input(i)\n \n#Input the information\ndef input(i):\n #Enter information; User input\n invtry[i].item=\"Gloves\"\n invtry[i].cost=10\n invtry[i].retail=25\n invtry[i].on_hand=50\n invtry[i].lead_time=10\n \n#Modify an existing item\ndef update():\n name=\"Gloves\" #User input\n for i in range(size):\n if not(name==invtry[i].item):\n break\n if i==size:\n print \"Item not found.\"\n return\n print \"Enter new information.\"\n input(i)\n \n#Display the list\ndef display():\n for t in range(size):\n if not(invtry[t].item==None):\n print invtry[t].item\n print \"Cost: $\",invtry[t].cost\n print \"Retail: $\",invtry[t].retail\n print \"On hand: \",invtry[t].on_hand\n print \"Resupply time: \",invtry[t].lead_time,\" days\"\n \n\ninit_list()\nwhile True:\n choice=menu()\n if choice==4:\n enter()\n elif choice==3:\n display()\n elif choice==2:\n update()\n elif choice==1:\n break",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "(E)nter\n(D)isplay\n(U)pdate\n(Q)uit\nchoose one: \n(E)nter\n(D)isplay\n(U)pdate\n(Q)uit\nchoose one: \nGloves\nCost: $ 10\nRetail: $ 25\nOn hand: 50\nResupply time: 10 days\n(E)nter\n(D)isplay\n(U)pdate\n(Q)uit\nchoose one: \nEnter new information.\n(E)nter\n(D)isplay\n(U)pdate\n(Q)uit\nchoose one: \n"
}
],
"prompt_number": 11
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.2, Page Number: 226<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''Pass a structure(class) to a function'''\n\n#Define a structure(class) type\nclass sample:\n a=None\n ch=None\n \ndef f1(parm):\n print parm.a,\" \",parm.ch\n\n#declare arg\narg=sample() \n\n#initialize arg\narg.a=1000\narg.ch='X'\n\n#call function\nf1(arg)\n ",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "1000 X\n"
}
],
"prompt_number": 12
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.3, Page Number: 227<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''Demonstrate structure assignments.'''\n\nclass stype:\n a=None\n b=None\n\n#Variable declaration\nsvar1=stype()\nsvar2=stype()\n\nsvar1.a=svar1.b=10\nsvar2.a=svar2.b=20\n\nprint \"Structures before assignment.\"\nprint \"svar1: \",svar1.a,' ',svar1.b\nprint \"svar1: \",svar2.a,' ',svar2.b\n\nsvar2=svar1 #assign structures\n\n#Result\nprint \"\\nStructures before assignment.\"\nprint \"svar1: \",svar1.a,' ',svar1.b\nprint \"svar1: \",svar2.a,' ',svar2.b",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Structures before assignment.\nsvar1: 10 10\nsvar1: 20 20\n\nStructures before assignment.\nsvar1: 10 10\nsvar1: 10 10\n"
}
],
"prompt_number": 13
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.4, Page Number: 230<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''This program displays the current system time.'''\n\nimport datetime\n\ndate=datetime.datetime.now()\n\n#Result\nprint date.time()",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "17:06:28.236000\n"
}
],
"prompt_number": 14
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.5, Page Number: 231<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''This program displays the current system time.'''\n\nimport datetime\n\ndate=datetime.datetime.now()\n\n#Result\nprint date.ctime()",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Sat Sep 14 17:07:14 2013\n"
}
],
"prompt_number": 15
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.6, Page Number: 232<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''Demonstrate a reference to a structure'''\n\nclass mystruct:\n a=None\n b=None\n\n#Recieve and return by reference\ndef f(var):\n var[0].a=var[0].a*var[0].a\n var[0].b=var[0].b/var[0].b\n return var[0]\n \n#Variable declaration\nx=[]\nx.append(mystruct())\ny=mystruct()\n\n#Initializing\nx[0].a=10\nx[0].b=20\n\nprint \"Original x.a and x.b: \",x[0].a,' ',x[0].b\n\ny=f(x) #function call\n\n#Result\nprint \"Modified x.a and x.b: \",x[0].a,' ',x[0].b\nprint \"Modified y.a and y.b: \",y.a,' ',y.b\n\n",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Original x.a and x.b: 10 20\nModified x.a and x.b: 100 1\nModified y.a and y.b: 100 1\n"
}
],
"prompt_number": 16
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.7, Page Number: 239<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''Use a union to exchange the bytes within a short integer'''\n#Class used in place of union \n\nclass swap_bytes:\n ch=[0,0]\n\n#Exchange of bytes\ndef disp_binary(u):\n t=128\n while not(t==0):\n if u&t:\n print \"1 \",\n else:\n print \"0 \",\n t=t/2\n\n#Variable declaration\nsb=swap_bytes()\n\nsb.ch[0]=15\n\nprint \"Original bytes: \",\ndisp_binary(sb.ch[1])\ndisp_binary(sb.ch[0])\n\n#Exchange bytes\ntemp=sb.ch[0]\nsb.ch[0]=sb.ch[1]\nsb.ch[1]=temp\n\n#Result\nprint \"\\nExchanged bytes: \",\ndisp_binary(sb.ch[1])\ndisp_binary(sb.ch[0])\n\n\n ",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Original bytes: 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 \nExchanged bytes: 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 \n"
}
],
"prompt_number": 17
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.8, Page Number: 240<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''Display the ASCII code in binary for characters'''\n\n#Variable declaration\nch='a'\n\nwhile True:\n print \"\\n\",ch,\n print bin(ord(ch)) #Display the bit pattern for each character\n ch=chr(ord(ch)+1)\n if ch=='r':\n break",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "\na 0b1100001\n\nb 0b1100010\n\nc 0b1100011\n\nd 0b1100100\n\ne 0b1100101\n\nf 0b1100110\n\ng 0b1100111\n\nh 0b1101000\n\ni 0b1101001\n\nj 0b1101010\n\nk 0b1101011\n\nl 0b1101100\n\nm 0b1101101\n\nn 0b1101110\n\no 0b1101111\n\np 0b1110000\n\nq 0b1110001\n"
}
],
"prompt_number": 18
},
{
"cell_type": "markdown",
"metadata": {},
"source": "<h3>Example 10.9, Page Number: 242<h3>"
},
{
"cell_type": "code",
"collapsed": false,
"input": "'''Implementation of an example of union in python'''\n\n#Variable declaration\nch=['X','Y']\nc=\"\"\ndef disp_bits(u):\n t=128\n global c\n while not(t==0):\n if u&t:\n c=c+\"1\"\n else:\n c=c+\"0\"\n t=t/2 \n return c\n\n#Result\nprint \"union as chars: \",ch[0],ch[1]\nprint \"union as integer: \",\nc= disp_bits(ord(ch[1]))\nc= disp_bits(ord(ch[0]))\nprint int(str(c),2)\n\n\n",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "union as chars: X Y\nunion as integer: 22872\n"
}
],
"prompt_number": 19
},
{
"cell_type": "code",
"collapsed": false,
"input": "",
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
