Exercise 5 Solutions.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "# Analyzing and testing a program with binary search method\n",
    "def isPal(x):\n",
    "    assert type(x)==list\n",
    "    temp=x # Third bug, unsafe use for assignment of the list, Solution: try 'temp=x[:]' to copy 'x' list to 'temp' safely\n",
    "    #print(temp,x) # Fourth use of print, try to see what 'temp' and 'x' lists shows before and after reversion \n",
    "    temp.reverse # -> Second bug, Solution: temp.reverse()\n",
    "    #print(temp,x) # Third use of print, searching another potential bug on the upper half of the function\n",
    "    if temp==x:\n",
    "        return True\n",
    "    else:\n",
    "        return False\n",
    "        \n",
    "def silly(n):\n",
    "    #result=[] -> Solution for the first bug, place it outside of the loop\n",
    "    for i in range(n):\n",
    "        result=[] # -> First bug, causing the 'result' list to be empty list each time in the loop\n",
    "        elem=raw_input('Enter element: ')\n",
    "        result.append(elem)\n",
    "        #print(result) -> Second use of print, to see the 'result' more detailed within the 'for' loop   \n",
    "    #print(result) -> First use of print, searching the potential bug on the upper half of the code   \n",
    "    if isPal(result): #Make sure the upper half of the code dosen't include any bugs, then search other bugs in other half\n",
    "        print('Yes')\n",
    "    else:\n",
    "        print('No')\n",
    "        \n",
    "# k,a,y,a,k  m,a,k,a,m  /  z,a,m,a,n  \n",
    "\n",
    "# Try palindrome and non-palindrome sequences for testing the 'silly' function\n",
    "silly(5)\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "#Example for using time function for calculating elapsed time in a program\n",
    "import time\n",
    "\n",
    "start_time = time.time() # Setting starting time (time.time())\n",
    "#------------------------------------------------------------\n",
    "i=0\n",
    "loop_range = 100000000 # try to increase or decrease 'loop_range' variable and see the results for 'elapsed_time' variable\n",
    "while i<loop_range:\n",
    "    i=i+1\n",
    "#------------------------------------------------------------\n",
    "elapsed_time = time.time() - start_time # Setting ending time (time.time()) and subtracting start time from it\n",
    "print elapsed_time\n"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 2",
   "language": "python",
   "name": "python2"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 2
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython2",
   "version": "2.7.9"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}