task 1

#!/usr/bin/env python3

import random
import operator
import json

operators = {
    "+": operator.add,
    "/": operator.floordiv,
    "-": operator.sub,
    "*": operator.mul
}

def prompt_int(prompt):
    while True:
        try:
            return int(input(prompt).strip())
        except ValueError:
            print("Not a valid whole number, try again.")

QUESTIONS = 10 # total question count
MAX_DIVISION_VALUE = 12 # maximum answer for division questions
MAX_GENERAL_VALUE = 50 # maximum size of operand for addition/subtraction
MAX_MULTIPLICATION_VALUE = 24 # maximum size of operand for multiplication
CLASSES = ["1", "2", "3"] # classes a student can be in

def do_quiz():
    name = input("Name: ")
    while True:
        class_ = input("Class: ").lower().strip() # class is a reserved keyword in Python, so use class_ instead
        if class_ in CLASSES: break
        else: print("No such class", class_)

    score = 0
    for _ in range(QUESTIONS):
        # randomly pick one of division, subtraction, multiplication or addition
        operation = random.choice(list(operators.keys()))

        # pick questions which only require integer division
        if operation == "/":
            b = random.randint(2, MAX_DIVISION_VALUE)
            a = b * random.randint(2, MAX_DIVISION_VALUE)
        # generate smaller questions for multiplication
        elif operation == "*":
            a = random.randint(1, MAX_MULTIPLICATION_VALUE)
            b = random.randint(1, MAX_MULTIPLICATION_VALUE)
        else:
            a = random.randint(1, MAX_GENERAL_VALUE)
            b = random.randint(1, MAX_GENERAL_VALUE)

        # display question
        print(f"{a} {operation} {b}")
        # calculate answer and compare with input
        correct_answer = operators[operation](a, b)
        if prompt_int("Answer: ") == correct_answer:
            print("Correct!")
            score += 1
        else:
            print(f"Incorrect. The answer is {correct_answer}.")

    # print totals
    print(f"You got {score}/{QUESTIONS} right ({score / QUESTIONS * 100}%).")

    # write score to file (as newline-delimited JSON, to avoid possible escaping issues and for easy parsing, including by other tools)
    with open("scores.jsonl", "a") as file:
        json.dump({ "class": class_, "score": score, "student": name }, file)
        file.write("\n")

def display_scores():
    with open("scores.jsonl", "r") as file:
        lines = [ line.strip() for line in file.readlines() ]

    scores_seen = {}
    best_scores = {}
    # read file backward to get latest scores first
    for line in reversed(lines):
        # parse JSON
        quiz_result = json.loads(line)
        name = quiz_result["student"]
        class_ = quiz_result["class"]
        score = quiz_result["score"]
        # uniquely identify student by their name and class
        student = (name, class_)
        # check if 3 scores for a student have already been processed
        times_seen = scores_seen.get(student, 0)
        if times_seen < 3:
            scores_seen[student] = times_seen + 1
            # check if score is better than current best
            best_score = best_scores.get(student, None)
            if best_score == None or score > best_score:
                best_scores[student] = score

    # sort student, best score tuples by student name
    alphabetical_scores = sorted(best_scores.items(), key=lambda student_and_score: student_and_score[0])
    for (name, class_), score in alphabetical_scores:
        print(f"{name} (class {class_}): {score}")

if "y" in input("Display scores? ").lower():
    display_scores()
else:
    do_quiz()