{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d620068e",
   "metadata": {},
   "outputs": [],
   "source": [
    "for i in range(5):\n",
    "    for j in range(4):\n",
    "        print(\"pineapple\")\n",
    "        "
   ]
  },
  {
   "cell_type": "markdown",
   "id": "93494dbc",
   "metadata": {},
   "source": [
    "break statement"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "9e499577",
   "metadata": {},
   "outputs": [],
   "source": [
    "while True:\n",
    "    answer = float(input(\"Enter a positive number: \"))\n",
    "    if answer > 0:\n",
    "        number = answer\n",
    "        break\n",
    "    print(\"That is not a positive number. Try again.\")\n",
    "\n",
    "print(\"You entered\", number)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "ba2b1014",
   "metadata": {},
   "outputs": [],
   "source": [
    "# Pin number, 3 trials\n",
    "correct_pin = \"1234\"\n",
    "\n",
    "for attempt in range(3):        \n",
    "    pin = input(\"Enter your PIN: \")\n",
    "    if pin == correct_pin:\n",
    "        print(\"Access granted\")\n",
    "        break                   # correct PIN, allow access\n",
    "    print(\"Wrong PIN, try again\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "b0cc9900",
   "metadata": {},
   "outputs": [],
   "source": [
    "# Pin number, 3 trials\n",
    "correct_pin = \"1234\"\n",
    "\n",
    "for attempt in range(3):        \n",
    "    pin = input(\"Enter your PIN: \")\n",
    "    if pin == correct_pin:\n",
    "        print(\"Access granted\")\n",
    "        break                   # correct PIN, allow access\n",
    "    if attempt != 2:\n",
    "        print(\"Wrong PIN, try again\")\n",
    "    else:\n",
    "        print(\"No attempts left\")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f6aae59f",
   "metadata": {},
   "source": [
    "Άσκηση"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d785be75",
   "metadata": {},
   "outputs": [],
   "source": [
    "# A\n",
    "a_n = 0\n",
    "\n",
    "n = 1\n",
    "\n",
    "while True: \n",
    "    a_n += 1/n\n",
    "    n += 1\n",
    "\n",
    "    if n > 100:\n",
    "        break\n",
    "    \n",
    "print(f'A_n = {a_n:.5f}')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "91b8b2f5",
   "metadata": {},
   "outputs": [],
   "source": [
    "# B & C\n",
    "tol = 1e-7          \n",
    "a_n = 0\n",
    "n = 1\n",
    "\n",
    "while True:\n",
    "    if 1/n < tol:\n",
    "        break\n",
    "    a_n = a_n + 1/n\n",
    "    n += 1\n",
    "\n",
    "print(f\"A = {a_n:.5f}, added terms = {n-1}\")"
   ]
  }
 ],
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