{
"metadata": {
"name": "",
"signature": "sha256:9c17589f9344a35ddc3dd493523efe0d9a1cf9ad387dc72f15338d1f77f12b62"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 5: Arrays and Pointers"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.1, page no. 137"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''\n",
"python does not have pointer functionality.We can get it explicitly.\n",
"'''\n",
"\n",
"class ref:\n",
" def __init__(self, obj): self.obj = obj\n",
" def get(self): return str(self.obj)\n",
" def set(self, obj): self.obj = obj\n",
"\n",
"\n",
"x=ref([0])\n",
"p=x # assigning variable value to p\n",
"\n",
"p.set(0) # set x to zero */\n",
"print \"\\nx is \" + x.get()\n",
"print \"\\np is \" + p.get()\n",
"a = p.get()\n",
"p.set(int(a)+1) # increment what p points to */\n",
"print \"\\nx is \" +x.get()\n",
"a = p.get()\n",
"p.set(int(a)+1) # increment what p points to */\n",
"print \"\\nx is \" + x.get()"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"x is 0\n",
"\n",
"p is 0\n",
"\n",
"x is 1\n",
"\n",
"x is 2\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.2, page no. 139"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"def date(a,b): # /* declare the function */\n",
" day_ret =0\n",
" month_ret = 0\n",
" ''' At this point, calculate the day and month\n",
" * values in day_ret and month_ret respectively.\n",
" '''\n",
" a = day_ret;\n",
" b = month_ret;\n",
" return a,b\n",
"\n",
"\n",
"\n",
"\n",
"month = 5\n",
"day = 1\n",
"d,m = date(day,month);\n",
"print \"day is %d, month is %d\\n\" %(d, m)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"day is 0, month is 0\n",
"\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.3, page no. 142"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from array import array\n",
"\n",
"ARSZ=20\n",
"ar=[]\n",
"\n",
"for i in range(ARSZ + 1):\n",
" ar.append( i)\n",
" print \"ar[%d] now = %d\\n\" %( i, ar[i])"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"ar[0] now = 0\n",
"\n",
"ar[1] now = 1\n",
"\n",
"ar[2] now = 2\n",
"\n",
"ar[3] now = 3\n",
"\n",
"ar[4] now = 4\n",
"\n",
"ar[5] now = 5\n",
"\n",
"ar[6] now = 6\n",
"\n",
"ar[7] now = 7\n",
"\n",
"ar[8] now = 8\n",
"\n",
"ar[9] now = 9\n",
"\n",
"ar[10] now = 10\n",
"\n",
"ar[11] now = 11\n",
"\n",
"ar[12] now = 12\n",
"\n",
"ar[13] now = 13\n",
"\n",
"ar[14] now = 14\n",
"\n",
"ar[15] now = 15\n",
"\n",
"ar[16] now = 16\n",
"\n",
"ar[17] now = 17\n",
"\n",
"ar[18] now = 18\n",
"\n",
"ar[19] now = 19\n",
"\n",
"ar[20] now = 20\n",
"\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.4 & 5.5, page no. 146"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"ARSZ = 10\n",
"\n",
"fp1= ARSZ\n",
"fp2=0\n",
"\n",
"\n",
"while(fp2 != fp1):\n",
" print \"Difference: %d\\n\" %((ARSZ-fp1))\n",
" fp1 -= 1"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Difference: 0\n",
"\n",
"Difference: 1\n",
"\n",
"Difference: 2\n",
"\n",
"Difference: 3\n",
"\n",
"Difference: 4\n",
"\n",
"Difference: 5\n",
"\n",
"Difference: 6\n",
"\n",
"Difference: 7\n",
"\n",
"Difference: 8\n",
"\n",
"Difference: 9\n",
"\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.6, page no. 149"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"s = raw_input(\"Enter String:\")\n",
"print len(s)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter String:python \n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"7\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.7, page no. 150"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"def str_eq(s1,s2):\n",
" if s1==s2:\n",
" return True\n",
" return False\n",
"\n",
"print str_eq(\"this\",\"hello\")\n",
"print str_eq(\"this\",\"this\")"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"False\n",
"True\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.8, page no. 151"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"cp = \"a string\";\n",
"for i in cp:\n",
" print i,\n",
"\n",
"print \"\\n\"\n",
"for i in range(len(cp)):\n",
" print cp[i],"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a s t r i n g \n",
"\n",
"a s t r i n g\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.9, page no. 152"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import numpy\n",
"\n",
"ARLEN=10\n",
"ar = numpy.zeros(ARLEN)\n",
"\n",
"print ar"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.]\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.10, page no. 158"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''\n",
"Python does not have any concept of pointer.\n",
"Python will go same for all mentioned.\n",
"'''\n",
"\n",
"\n",
"MAXSTRING=50 # /* max no. of strings */\n",
"MAXLEN = 80 #/* max length. of strings */\n",
"\n",
"strings = [] # list of strings\n",
"\n",
"def print_arr(a):\n",
" print a\n",
"\n",
"\n",
"def sort_arr(a):\n",
" a.sort()\n",
" return a\n",
"\n",
"\n",
"def next_string():\n",
" s = raw_input(\"Enter Next String : \")\n",
" strings.append(s)\n",
" return s\n",
"\n",
"nstrings = 0\n",
"\n",
"while(nstrings < MAXSTRING and next_string() != '0'):\n",
" nstrings += 1\n",
"\n",
"print_arr(strings)\n",
"print sort_arr(strings)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter Next String : abc\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter Next String : def\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter Next String : fed\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter Next String : 0\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"['abc', 'def', 'fed', '0']\n",
"['0', 'abc', 'def', 'fed']\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.13, page no. 165"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''\n",
"We need not to worry about memory allocation and deallocation in python.\n",
"It is simple to get a string, print and copy it.\n",
"'''\n",
"\n",
"\n",
"str_p = \"\"\n",
"tmp_p = \"\"\n",
"\n",
"str_p = raw_input(\"Enter String.. : \")\n",
"next_p = str_p\n",
"chars_read = len(str_p)\n",
"\n",
"\n",
"tmp_p = str_p\n",
"\n",
"print tmp_p\n",
"\n",
"\n",
"print str_p"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter String.. : hello\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"hello\n",
"hello\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.14, page no. 165"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"arr = \"hello\"\n",
"a = arr\n",
"print \"Size of arr %d\\n\" % len(arr)\n",
"print \"Size of a %d\\n\" % len(a)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Size of arr 5\n",
"\n",
"Size of a 5\n",
"\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.16, page no. 167"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"def func(arg):\n",
"\tprint \"%d\\n\" %(arg)\n",
"\n",
"func(5)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"5\n",
"\n"
]
}
],
"prompt_number": 10
}
],
"metadata": {}
}
]
}