{
"metadata": {
"name": "",
"signature": "sha256:6212a1681da4032325cbede0a51614855911a11a6baad9f5e6fd0a0ecd4b5da9"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 9: Functions"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example average.c, Page 185"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def average(a,b): #function to calculate average\n",
" return (a+b)/2\n",
"nums = raw_input(\"Enter three numbers: \") #input numbers from user\n",
"list1 = map(float, nums.split()) \n",
"x=list1[0]\n",
"y=list1[1]\n",
"z=list1[2]\n",
"print \"Average of %.1f and %.1f: %.2f\" % (x,y,average(x,y)) #print average using function\n",
"print \"Average of %.1f and %.1f: %.2f\" % (y,z,average(y,z))\n",
"print \"Average of %.1f and %.1f: %.2f\" % (x,z,average(x,z))\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter three numbers: 3.5 9.6 10.2\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Average of 3.5 and 9.6: 6.55\n",
"Average of 9.6 and 10.2: 9.90\n",
"Average of 3.5 and 10.2: 6.85\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example countdown.c, Page 186"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def print_count(n): #function definition\n",
" print \"T minus %d and counting\" % n\n",
"for i in range (10,0,-1):\n",
" print_count(i) #print using function\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"T minus 10 and counting\n",
"T minus 9 and counting\n",
"T minus 8 and counting\n",
"T minus 7 and counting\n",
"T minus 6 and counting\n",
"T minus 5 and counting\n",
"T minus 4 and counting\n",
"T minus 3 and counting\n",
"T minus 2 and counting\n",
"T minus 1 and counting\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example pun2.c, Page 187"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def print_pun(): #function definition\n",
" print \"To C, or not to C: that is the question.\"\n",
"print_pun() #function call"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"To C, or not to C: that is the question.\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example prime.c, Page 190"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def is_prime(n): #function to check for prime number\n",
" if (n<=1):\n",
" return False\n",
" divisor=2\n",
" while(divisor*divisor<=n):\n",
" if(n%divisor==0):\n",
" return False\n",
" return True\n",
"n=int(raw_input(\"Enter a number: \")) #input number\n",
"if(is_prime(n)): #check if prime using function\n",
" print \"Prime\" #print result of check\n",
"else:\n",
" print \"Not prime\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter a number: 34\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Not prime\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example on Page 192"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def main():\n",
" nums = raw_input(\"Enter three numbers: \") #input numbers from user\n",
" list1 = map(float, nums.split()) \n",
" x=list1[0]\n",
" y=list1[1]\n",
" z=list1[2]\n",
" \n",
" #function usage before definition\n",
" \n",
" print \"Average of %.1f and %.1f: %.2f\" % (x,y,average(x,y)) #print average using function\n",
" print \"Average of %.1f and %.1f: %.2f\" % (y,z,average(y,z))\n",
" print \"Average of %.1f and %.1f: %.2f\" % (x,z,average(x,z))\n",
" \n",
"if __name__==\"__main__\":\n",
" main()\n",
" \n",
"def average(a,b): #function to calculate average\n",
" return (a+b)/2"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter three numbers: 3.5 9.6 10.2\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Average of 3.5 and 9.6: 6.55\n",
"Average of 9.6 and 10.2: 9.90\n",
"Average of 3.5 and 10.2: 6.85\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example on Page 195"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"x=3.0\n",
"print \"Square: %d\" % square(x) #gives error since function prototype doesnt exist before\n",
"def square(n):\n",
" return n*n\n",
"\n",
"\"\"\"\n",
"def main():\n",
" x=3.0\n",
" print \"Square: %d\" % square(x) \n",
" \n",
"#Now wouldn't give an error since writing the line below loads up all functions before starting main()\n",
"\n",
"if __name__==\"__main__\":\n",
" main()\n",
" \n",
"def square(n):\n",
" return n*n\n",
"\"\"\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"ename": "NameError",
"evalue": "name 'square' is not defined",
"output_type": "pyerr",
"traceback": [
"\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mNameError\u001b[0m Traceback (most recent call last)",
"\u001b[1;32m<ipython-input-3-2c761040ea35>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m 1\u001b[0m \u001b[0mx\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m3.0\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 2\u001b[1;33m \u001b[1;32mprint\u001b[0m \u001b[1;34m\"Square: %d\"\u001b[0m \u001b[1;33m%\u001b[0m \u001b[0msquare\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;31m#gives error since function prototype doesnt exist before\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 3\u001b[0m \u001b[1;32mdef\u001b[0m \u001b[0msquare\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mn\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 4\u001b[0m \u001b[1;32mreturn\u001b[0m \u001b[0mn\u001b[0m\u001b[1;33m*\u001b[0m\u001b[0mn\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
"\u001b[1;31mNameError\u001b[0m: name 'square' is not defined"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example on Page 197"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def store_zeroes(a,n):\n",
" for i in range(0,n):\n",
" a[i]=0\n",
"b=[None]*200\n",
"store_zeroes(b,100) #First 100 elements of b are now 100.\n",
"print b"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example qsort.c, Page 207"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"N=10 #number of elements to sort\n",
"def split(a,low,high): #function to split list while sorting\n",
" part_element=a[low]\n",
" while(1):\n",
" while(low<high and part_element<=a[high]):\n",
" high=high-1\n",
" if(low>=high):\n",
" break\n",
" a[low+1]=a[high]\n",
" \n",
" while(low<high and a[low]<=part_element):\n",
" low=low+1\n",
" if(low>=high):\n",
" break\n",
" a[high-1]=a[low]\n",
" \n",
" a[high]=part_element\n",
" return high\n",
" \n",
"def quicksort(a,low,high): #recursive function for quicksort\n",
" if(low>=high):\n",
" return\n",
" middle=split(a,low,high)\n",
" quicksort(a,low,(middle-1))\n",
" quicksort(a,(middle+1),high)\n",
" \n",
"nums = raw_input(\"Enter %d numbers to be sorted: \"%N) #input numbers to sort\n",
"a = map(int, nums.split())\n",
"a.sort()\n",
"quicksort(a,0,(N-1)) #call quicksort function\n",
"print \"In sorted order: \", #print sorted result\n",
"for i in a:\n",
" print i,\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"stream": "stdout",
"text": [
"Enter 10 numbers to be sorted: 9 16 47 82 4 66 12 3 25 51\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"In sorted order: 3 4 9 12 16 25 47 51 66 82\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}