Section1Problem.m

%% Section 1 Problem 
% In this problem, you will use either a cell or structure array to store a 
% database of classes taken by student X while at Stanford University.  Subsequently, 
% the data structure will be used to compute the Grade Point Average (GPA) and 
% other measures of academic performance for student X.
%% Task 1
% Download a text file |courses.txt| containing a list of courses/grades and 
% a function |read_courses.m| that loads the contents of |courses.txt| into a 
% cell array. Feel free to use/modify the code below.

g = read_courses('courses.txt');
%% 
% Here is the content of g:
% 
% * |g{i,1}| - cell array for course number (cross-listings not included)
% * |g{i,2}| - string containing course title
% * |g{i,3}| - string containing term course was taken
% * |g{i,4}| - double containing number of units
% * |g{i,5}| - string specifying whether pass/not pass or letter grade
% * |g{i,6}| - string containing grade
% 
% Note for Stanford students:  The format used in |courses.txt| is exactly 
% the format obtained by copy/pasting one's courses from Axess (under "Course 
% History'') into a text file.  Therefore, you can use the code from this problem 
% to compute your own GPA and related statistics without having to go through 
% course-by-course and enter the data manually.  For this assignment,  submit 
% only the output corresponding to |courses.txt|, not your own grades.
% 
% 
%% Task 2
% Load output of |read_courses| into a convenient structure array with fields 
% of your choosing.    _Warning_ - This will involve parsing strings such as '|AA210A|' 
% to obtain the department |'AA'| and the course number |'210A' |and '|2012-2013 
% Winter|' to obtain the quarter ('|Winter|') and year (|2013|) the course was 
% taken.
% 
% As I have not discussed string parsing, I have provided you with a function 
% |make_course_struct.m| that takes the output of |read_courses| and parses the 
% text in the cell array to a more useful form in a structure array.
% 
% Feel free to use/modify the code below or make your own structure.

courses = make_course_struct(g);
%% 
% Now, let's talk about Grade Point Average. Grade point average of class 
% set $$S$ $ is defined as
% 
% $$        \text{GPA} = \frac{1}{\sum_{c \in S_L} u(c)}\sum_{s \in S_L} 
% g(s)*u(s)$$
% 
%      where $ $S_L \subseteq S$ $is the subset of classes in $$S$$ taken 
% for a _letter _grade, $$g(c)$$ and $$u(c)$$ are the grade letter value and number 
% of units of class $$c \in S$$, respectively.  The letter grade mapping from 
% letter grade to letter grade value can be found <http://studentaffairs.stanford.edu/registrar/students/gpa-how 
% here>. The letter grade mapping is also taken care of in |make_course_struct.m| 
% if you choose to use it.
%%   Task 3
% Use the above data structure to:
% 
% * Compute GPA for set of all classes
% * Create a bar graph of number of units vs. department
% * Create a bar graph of GPA vs. quarter taken (Autumn, Winter, Spring, Summer)
% * Create a bar graph of GPA vs. quater _and _year in Stanford career that 
% class was taken (1st, 2nd, ...). Note that we define Year 1 at Stanford as the 
% academic year starting the _Autumn_ quarter you arrived at Stanford.  Any class 
% taken the summer before your first Autumn quarter would be considered a 0-th 
% year. This was taken care of in |make_course_struct.m| for you.
% * Compute total number of classes taken
% * Compute total number of graduation units (includes those taken for letter 
% grade and P/NP)
% 
% Feel free to use a box below to write a code.

%Write your code here%
% compute GPA
gpa = GPA(courses)

% find department with highest number of units
depts = unique({courses.department});
n = length(depts);
total_gpa_units = zeros(n,1);
for i=1:n
    total_gpa_units(i) = sum([courses(strcmp({courses.department}, depts{i})==1).gpa_units]);
end
[val, idx] = max(total_gpa_units);
dept_with_max_units = depts(idx)

% find the quarter with the lowerst GPA
qtrs = unique({courses.quarter});
m = length(qtrs);
qtr_gpas = zeros(m,1);
for i=1:m
    qtr_gpas(i) = GPA(courses(strcmp({courses.quarter}, qtrs{i})==1));
end
[val, idx] = min(qtr_gpas);
qtr_with_min_gpa = qtrs(idx)

% difference between first and last quarter
courses_first_qtr = courses(strcmp({courses.quarter}, 'Summer')==1 & [courses.academic_year]==0);
courses_last_qtr = courses(strcmp({courses.quarter}, 'Winter')==1 & [courses.academic_year]==3);
gpa_first_qtr = GPA(courses_first_qtr);
gpa_last_qtr = GPA(courses_last_qtr);

gpa_diff = gpa_first_qtr - gpa_last_qtr;

% Calculate the total number of classes taken
num_classes_taken = length(courses);

% total number of graudation units
total_grad_units = sum([courses.grad_units]);
%% Checkpoint
% Please answer the following questions and put the answers in the EdX page:
% 
% (A) What is the cumulative GPA? Round it to the nearest hundredth.
% 
% (B) Which department is associated with the highest number of units?
% 
% (C) Which quarter is associated with the lowest GPA?
% 
% (D) What is the difference GPA between the first quarter and the last quarter 
% in the record? Answer as an absolute value rounded to the nearest hundredth.
% 
% (E) What is the total number of classese taken?
% 
% (F) What is the total number of graduation units (includes those taken 
% for letter grade and P/NP)?