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   "source": [
    "# Hello"
   ]
  },
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   "id": "4200d243",
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   "source": [
    "\"\"\"\n",
    "     Example to show scope of variable in a main() program.\n",
    "\n",
    "\"\"\"\n",
    "\n",
    "ag = 34.56            #     Define in three global values.\n",
    "bg = 41.45\n",
    "x = 100.0\n",
    "\n",
    "def main():\n",
    "    \"\"\"\n",
    "    The main programme\n",
    "    \"\"\"\n",
    "    global ag         # Make ag writable within main() \n",
    "    #       Print out values, not bg can be read.\n",
    "    print(\"Value of ag in main is : \" + str(ag) + \" and  bg is : \" + str(bg))\n",
    "\n",
    "    ag +=  10         # Undate value of ag inside main()\n",
    "    print(\"New Value is ag is : \" + str(ag))\n",
    "\n",
    "    x = 30.0          # Declare x inside main (note NEW variable) and NOT global.\n",
    "    print(\"Internal value of x is : \" + str(x))\n",
    "    \n",
    "#      Run main rogram\n",
    "main()\n",
    "#      Do an external print to check globals.\n",
    "print(\"External value of ag is : \" + str(ag))\n",
    "print(\"External value of x is : \" + str(x))"
   ]
  }
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