{
"metadata": {
"name": "",
"signature": "sha256:e28261ed5c0b0cf7c10e8c91bd2debc8e99bf24519225a056fc19ed619f1e95d"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"CHAPTER 14: OPERATIONS ON BITS"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:449"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"def showbits(x):\n",
" return bin(x)[2:].zfill(16)\n",
"for j in range(0,6,1):\n",
" print \"Decimal %d is same as binary\" % (j)\n",
" print showbits(j)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Decimal 0 is same as binary\n",
"0000000000000000\n",
"Decimal 1 is same as binary\n",
"0000000000000001\n",
"Decimal 2 is same as binary\n",
"0000000000000010\n",
"Decimal 3 is same as binary\n",
"0000000000000011\n",
"Decimal 4 is same as binary\n",
"0000000000000100\n",
"Decimal 5 is same as binary\n",
"0000000000000101\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:450"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"def showbits(x):\n",
" return bin(x)[2:].zfill(16)\n",
"for j in range(0,4,1):\n",
" print \"Decimal %d is same as binary\" % (j)\n",
" print showbits(j)\n",
" k=j^65535 #using xor for making one's complement\n",
" print \"One's complement of %d is\" % (j)\n",
" print showbits(k)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Decimal 0 is same as binary\n",
"0000000000000000\n",
"One's complement of 0 is\n",
"1111111111111111\n",
"Decimal 1 is same as binary\n",
"0000000000000001\n",
"One's complement of 1 is\n",
"1111111111111110\n",
"Decimal 2 is same as binary\n",
"0000000000000010\n",
"One's complement of 2 is\n",
"1111111111111101\n",
"Decimal 3 is same as binary\n",
"0000000000000011\n",
"One's complement of 3 is\n",
"1111111111111100\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:451"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"import sys\n",
"def encrypt():\n",
" try:\n",
" fs=open('SOURCE.txt','r') #normal file\n",
" ft=open('TARGET.txt','w') #encrypted file\n",
" except:\n",
" print \"File opening error!\"\n",
" sys.exit(1)\n",
" while True:\n",
" ch=fs.read(1)\n",
" if not ch:\n",
" break\n",
" ft.write(bytearray([ord(ch)^0xff]))\n",
" fs.close()\n",
" ft.close()\n",
"encrypt()"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:452"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"def showbits(x):\n",
" return bin(x)[2:].zfill(16)\n",
"i=5225\n",
"print \"Decimal %d is same as binary\" % (i)\n",
"print showbits(i)\n",
"for j in range(0,6,1):\n",
" k=i>>j #right shift operator\n",
" print \"%d right shift %d gives\" % (i,j)\n",
" print showbits(k)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Decimal 5225 is same as binary\n",
"0001010001101001\n",
"5225 right shift 0 gives\n",
"0001010001101001\n",
"5225 right shift 1 gives\n",
"0000101000110100\n",
"5225 right shift 2 gives\n",
"0000010100011010\n",
"5225 right shift 3 gives\n",
"0000001010001101\n",
"5225 right shift 4 gives\n",
"0000000101000110\n",
"5225 right shift 5 gives\n",
"0000000010100011\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:453-454"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"def showbits(x):\n",
" return bin(x)[2:].zfill(16)\n",
"i=5225\n",
"print \"Decimal %d is same as binary\" % (i)\n",
"print showbits(i)\n",
"for j in range(0,5,1):\n",
" mask = 2 ** 16 - 1\n",
" k = (i << j) & mask #left shift operator\n",
" print \"%d right shift %d gives\" % (i,j)\n",
" print showbits(k)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Decimal 5225 is same as binary\n",
"0001010001101001\n",
"5225 right shift 0 gives\n",
"0001010001101001\n",
"5225 right shift 1 gives\n",
"0010100011010010\n",
"5225 right shift 2 gives\n",
"0101000110100100\n",
"5225 right shift 3 gives\n",
"1010001101001000\n",
"5225 right shift 4 gives\n",
"0100011010010000\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:457-458"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"d=9\n",
"m=3\n",
"y=1990\n",
"date=(y-1980)*512+m*32+d\n",
"print \"Date=%u\\n\" % (date)\n",
"year=1980+(date>>9)\n",
"month=((date<<7)>>12)\n",
"day=((date<<11)>>11)\n",
"print \"Year=%u\" % (year)\n",
"print \"Month=%u\" % (month)\n",
"print \"Day=%u\" % (day)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Date=5225\n",
"\n",
"Year=1990\n",
"Month=163\n",
"Day=5225\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:460"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"i=65\n",
"print \"Value of i=%d\\n\" % (i)\n",
"j=i&32\n",
"if j==0:\n",
" print \"and its fifth bit is off\\n\"\n",
"else:\n",
" print \"and its fifth bit is on\\n\"\n",
"j=i&64\n",
"if j==0:\n",
" print \"whereas its sixth bit is off\\n\"\n",
"else:\n",
" print \"whereas its sixth bit is on\\n\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Value of i=65\n",
"\n",
"and its fifth bit is off\n",
"\n",
"whereas its sixth bit is on\n",
"\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:463"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"b=50\n",
"b=b^12 #XOR operator\n",
"print \"%d\\n\" % (b) #this will print 62\n",
"b=b^12\n",
"print \"%d\\n\" % (b) #this will print 50"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"62\n",
"\n",
"50\n",
"\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE ON PAGE:463-464"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"def showbit(n):\n",
" for i in range(15,-1,-1):\n",
" andmask=1<<i\n",
" k=n&andmask\n",
" if k==0:\n",
" print 0, \n",
" else:\n",
" print 1, \n",
" print \"\\n\"\n",
"showbit(32)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 \n",
"\n"
]
}
],
"prompt_number": 14
}
],
"metadata": {}
}
]
}