exam_results.py

# This program interactively asks about your exam marks, and reports the
# corresponding grades.
#
# Usage:
#
# $ python exam_results.py
#
# A session with the program might look like the following:
#
# $ python exam_results.py
# What marks did you get in Maths?
# > 63
# What marks did you get in Philosophy?
# > 54
# What marks did you get in Geography?
# > 71
# What marks did you get in Music?
# > 68
#
# Your grades:
#
# Maths: B
# Philosophy: C
# Geography: A
# Music: B

subjects = []

grade_boundaries = {
    'A': [70, 100],
    'B': [60, 69],
    'C': [50, 59],
    'D': [40, 49],
    'E': [30, 39],
    'F': [0, 29],
}

student_marks = {}
student_grades = {}

def main():
    get_subjects()
    get_marks()
    get_grades()
    print_grades()


def get_marks():
    for subject in subjects:
        while True:
            mark = input(f"What marks did you get in {subject}? ")
            if validate_mark(mark, subject):
                break

def validate_mark(mark, subject):
    try:
        mark = int(mark)
        if 0 <= mark <= 100:
            student_marks[subject] = mark
            return True
        else:
            print("Please enter a number between 0 and 100.")
            return False
    except ValueError:
        print("Please enter a valid number.")
        return False

def get_grades():
    for subject, mark in student_marks.items():
        for grade, boundary in grade_boundaries.items():
            if boundary[0] <= mark <= boundary[1]:
                student_grades[subject] = grade
                break

def print_grades():
    print("\nYour grades:\n\n" + "\n".join(f"{subject}: {grade}" for subject, grade in student_grades.items()))

def get_subjects():
    num_of_subjects = int(input("How many subjects have you taken? "))

    for i in range(num_of_subjects):
        subject = input(f"Subject {i + 1}: ")
        subjects.append(subject)

if __name__ == "__main__":
    main()

# TODO:
# * Implement the program as described in the comments at the top of the file.

# TODO (extra):
# * Modify the program to handle the case where the user enters an invalid mark
#   (such as 150, or -25.5, or "bananas")
# * Modify the program to ask the user for the subjects that they've taken.