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 "cells": [
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   "metadata": {},
   "source": [
    "## Exercise 6##\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "A function can call other functions. "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Create function that calculate squares. Call it square. Having just one parameter. \n",
    "    "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": []
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Create function that calculate sume of squares, using previsou function call it SumofSquares(), \n",
    "with a parameter def ListValues.  \n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": []
  },
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   "cell_type": "markdown",
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   "source": [
    "Call the fucntion using the follwoing data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "46"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "listValues=[2,4,1,5]\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "It is even possible for the function to call itself. \n",
    "These types of construct are termed as recursive functions."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Create a factorial function without recursion:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now the factorial function but using recursion"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "def factorial(x):\n",
    "    if x == 1:\n",
    "        return 1\n",
    "    else:\n",
    "        return (x * factorial(x-1))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Advantages \n",
    "* Complex task can be splited into smaller (and less complex) subtasks\n",
    "* Using recursion in sequence generation is esear that nested iteration\n",
    "* The code look clean and elegant.\n",
    "\n",
    "Disadvantages\n",
    "* Uses large ammont of memory and time.\n",
    "* Not easy to undertand logic of the code\n",
    "* Hard to debug.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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