[+] TT2

TT2/q3.py

@@ -0,0 +1,191 @@
+"""CSC110 Fall 2021: Term Test 2, Question 3 (Object Oriented Design)
+
+Module Description
+==================
+This module contains instructions for this question. There are TWO
+parts of this question, labelled "Part (a)", "Part (b)", etc.
+The comments in this file contain instructions on how to complete each part,
+so please read those comments carefully.
+
+SUBMIT THIS FILE FOR GRADING!
+
+Copyright and Usage Information
+===============================
+
+This file is provided solely for the personal and private use of students
+taking CSC110 at the University of Toronto St. George campus. All forms of
+distribution of this code, whether as given or with any changes, are
+expressly prohibited. For more information on copyright for CSC110 materials,
+please consult our Course Syllabus.
+
+This file is Copyright (c) 2021 Mario Badr and Tom Fairgrieve.
+"""
+from dataclasses import dataclass
+
+
+###################################################################################################
+# Modelling a Problem Domain
+###################################################################################################
+# In this question, you will model a new problem domain by designing classes in a similar style to
+# the food delivery system we studied in lecture.
+
+###################################################################################################
+# Description of the Problem Domain
+###################################################################################################
+# Your client is the University of Toronto. They want new software to manage the grades of their
+# students. The grade system will store:
+#   1. GRADES that each have the course id (e.g., 'CSC110Y'), term id (e.g., '20219'), and score in
+#   the course (i.e., an integer ranging from 0 to 100, inclusive).
+#   2. STUDENTS that each have a utorid (e.g., 'astudent') and a collection of grades.
+
+###################################################################################################
+# Part (a) - Entity data classes
+###################################################################################################
+# Your first task is to complete the two data classes below, which represent  the two main entities
+# in our computational model.  Read the provided docstrings and use them to complete each data class
+# body.
+#
+# Do NOT add any additional instance attributes or change the class docstring.
+# You do NOT need to add any representation invariants or doctest examples.
+
+@dataclass
+class Grade:
+    """A grade on Acorn.
+
+    Instance Attributes:
+       - course: the course (e.g., 'CSC110Y1') this grade was achieved in.
+       - term: the term (e.g., '20219') this grade was achieved in.
+       - score: an integer representing the grade achieved.
+    """
+    course: str
+    term: str
+    score: int
+
+
+@dataclass
+class Student:
+    """A student who can have courses grades on acorn.
+
+    Instance Attributes:
+        - utorid: the utorid of this student
+        - grades: a dictionary mapping a course (e.g., 'CSC110Y1') to the student's Grade in that
+            course.
+    """
+    utorid: str
+    grades: dict[str, Grade]
+
+
+###############################################################################
+# Part (b) - Manager class
+###############################################################################
+# The class below is responsible for keeping track of all instances of the entities in our
+# model and performing mutating operations on them.
+#
+# Read through the class and implement the methods that have empty bodies.
+# Do NOT change anything else in the class (attributes, methods that we have implemented).
+
+
+class AcornSystem:
+    """A class that tracks students and their grades."""
+
+    # Private Instance Attributes:
+    #   - _students: a dictionary mapping utorids to Students
+
+    def __init__(self, initial_students: list[Student]) -> None:
+        """Initialize a new AcornSystem, adding every student in initial_students to this system.
+
+        Precondition:
+            - Every student in initial_students has a unique utorid
+        """
+        self._students = {}
+        for student in initial_students:
+            self._students[student.utorid] = student
+
+    def student_count(self) -> int:
+        """Return the number of students in this system."""
+        return len(self._students)
+
+    def add_grade(self, utorid: str, grade: Grade) -> bool:
+        """Add grade to the student with utorid and return whether the grade was added successfully.
+
+        Do not add grade if the student with utorid already has a grade assigned for that course.
+
+        Preconditions:
+            - A student with utorid exists in this system
+        """
+        student = self._students[utorid]
+
+        if grade.course in student.grades:
+            return False
+        else:
+            student.grades[grade.course] = grade
+            return True
+
+    def get_grades(self, utorid: str, term: str) -> list[tuple[str, int]]:
+        """Return a list of tuples of the courses and scores that the student with utorid achieved
+        in term.
+
+        Preconditions:
+            - A student with utorid exists in this system
+            - The student in this system with utorid has a grade for course
+
+        >>> acorn_system = AcornSystem([Student('astudent', {})])
+        >>> acorn_system.add_grade('astudent', Grade('CLA204H1', '20209', 76))
+        True
+        >>> acorn_system.get_grades('astudent', '20209')
+        [('CLA204H1', 76)]
+        """
+        return [(g.course, g.score) for g in self._students[utorid].grades.values()
+                if g.term == term]
+
+    def amend_grades(self, utorid: str, amendments: dict[str, int]) -> int:
+        """Update the grades for the student with utorid based on the amendments, which maps courses
+        to the amended score.
+
+        Return the number of successful amendments made. An amendment is not successful if the
+        student has no grade on record for the course. No mutation should occur for students who
+        have no grade on record for course.
+
+        Preconditions:
+            - A student with utorid exists in this system
+
+        >>> acorn_system = AcornSystem([Student('astudent', {})])
+        >>> acorn_system.add_grade('astudent', Grade('CLA204H1', '20209', 76))
+        True
+        >>> acorn_system.amend_grades('astudent', {'CLA204H1': 80})
+        1
+        >>> acorn_system.get_grades('astudent', '20209')
+        [('CLA204H1', 80)]
+        """
+        grades = self._students[utorid].grades
+        count = 0
+        for course in amendments:
+            if course in grades:
+                grades[course].score = amendments[course]
+                count += 1
+        return count
+
+    def calculate_averages(self, utorids: list[str]) -> dict[str, float]:
+        """Return a dictionary mapping a student's utorid to the average grade they achieved for
+        all courses completed.
+
+        Preconditions:
+            - Every utorid in amendments is a student in this system
+
+        >>> acorn_system = AcornSystem([Student('astudent', {}), Student('bstudent', {})])
+        >>> acorn_system.add_grade('astudent', Grade('CLA204H1', '20209', 76))
+        True
+        >>> acorn_system.calculate_averages(['astudent'])
+        {'astudent': 76.0}
+        >>> acorn_system.add_grade('astudent', Grade('CLA205H1', '20219', 98))
+        True
+        >>> acorn_system.calculate_averages(['astudent'])
+        {'astudent': 87.0}
+        >>> acorn_system.add_grade('bstudent', Grade('CLA205H1', '20219', 98))
+        True
+        >>> temp = acorn_system.calculate_averages(['astudent', 'bstudent'])
+        >>> temp == {'astudent': 87.0, 'bstudent': 98.0}
+        True
+        """
+        return {u: sum(g.score for g in self._students[u].grades.values())
+                / len(self._students[u].grades) for u in utorids}