User Defined Functions Matlab: This problem requires you to explain sections of

Question

User Defined Functions Matlab:

This problem requires you to explain sections of code and to finish writing a user-written function to provide you with exposure to structures. Please look at the code listed below. For this problem, complete the following two items:

Respond to each of the 10 numbered prompts that appear in the comments of the code below. Your responses should be typed.
Complete the user-written function that calculates a student’s final grade.

Additional information:

Brief description of the code: (1) an array of assignment categories and their associated weights are stored (generally in response to user-input) (2) Then, points associated with each assignment within each category as stored. (3) The structure arrays created by step 1 and step 2 are passed to a user-defined function that calculates the final grade.

For example, the code can be used to calculate a course grade given the following information:

Six homework assignments, each out of ten points (altogether, 20% of the final grade)

Three midterms, each out of a hundred points (altogether, 50% of the final grade)

One final, out of 100 points (30% of the final grade).

This is the code:

Explanation / Answer

function Q7
clear
close all
clc

%% 9
fprintf(' 9) ')
requestUserInput = ~isempty(input('Would you like this script to accept user input? (press return for no)'));

%% 9-Category input
categories = {'Homework';'Midterm';'Final';'Done'};
weights = [20 50 30];
done = false;
idx = 1;
% 1) What is accomplished by this region?
% Ans 1) It asks for the categories from the user and then assign the weightage
% to each category as the user wants.
while ~done
    category = my_input(requestUserInput, categories{idx}, 'Enter an assignment category (or Done)', 's');
    if strcmp(category, 'Done')   % 2) What is accomplished by this region?
        done = true;              % Ans 2) It checks whether there is any category left or all done.
      
    else                          % 3) What is accomplished by this region?
        cats(idx).ID = idx;       % Ans 3) If a new category, assigns a ID, and weight to it.
        cats(idx).Type = category;
        cats(idx).Weight = my_input(requestUserInput, weights(idx), 'Enter a weight for this category (read as a %)');
        idx = idx + 1;
    end
end

userInputs = [7 8 7 9 8 9 -1 65 85 100 -1 100 -1];
worths = [10 10 10 10 10 10 100 100 100 100];
done = false;
idxCat = 1;
idxInputs = 1;
idxScore = 1;
%% 9-Grade input
% 4) What is accomplished by this region?
while ~done
    fprintf('Enter a %s score (or -1 for done) (# pts earned) ', cats(idxCat).Type);
    earned = my_input(requestUserInput, userInputs(idxInputs),''); % input ();
    if earned == -1 && idxCat == length(cats) % 5) What is accomplished by this region?
        done = true;                          % Ans 5) It checks whether scores has been entered for all the exams in all categories
    elseif earned == -1                       % 6) What is accomplished by this region?]
        idxCat = idxCat + 1;                  % Ans 6) It checks whether scores has been entered for all exams of a particular category, then move on to next
    else                                      % 7) What is accomplished by this region?
        scores(idxScore).ID = cats(idxCat).ID; % Ans 7) It fills the array of scores structure with the required values for a particular exam.
        scores(idxScore).Type = cats(idxCat).Type;
        scores(idxScore).Earned = earned;

        scores(idxScore).Worth = worths(idxScore);
        idxScore = length(scores) + 1;
    end
    idxInputs = idxInputs + 1;
end

finalgrade = calculateGrade (cats, scores);
fprintf('The final grade for this student is %.2f%% ',finalgrade);

end

%% 9 Functions:
% 8) What is accomplished by this function?
% Ans 8) This functions first checks whether user wants to provide
% input or not. If yes, then it prompts the user with the string passed in the
% parameter 'promptStr'. If no, then it returns the default value passed in
% the parameter variable 'fallback'.
function res = my_input(doPrompt, fallback, promptStr, option)
if doPrompt
    if nargin == 4
        res = input(promptStr,option);
    else
        res = input(promptStr);
    end
else
    res = fallback;
end
end

%% Complete the function below (function should calculate final grade and include the lines below)
function finalgrade = calculateGrade(cats, scores)
% Note: the square brackets used below group together all the fields of a
% structure array into there own array. (e.g. if we created an array of
% structures, 'persons', where there is one structure for each person in
% the class, then [persons.Age] would be an array of ages)
finalgrade = 0;
temp1 = 0;
temp2 = 0;
j = 0;
for i = 1:length(scores)
    % 9) Explain this line in your own words:
    % Ans 9) It finds the number of exams of a particular category.
    tot = sum(scores(i).ID == [scores.ID]);         % Number of points in an assignment category (e.g. 6 homework assignments)
    % 10) Explain this line in your own words:
    % Ans 10) It finds out the weightage of the exam of a particular category
    weight = cats(scores(i).ID == [cats.ID]).Weight; % Weight of that assignment category (e.g. homework is worth 20%)
  
    temp1 = temp1 + scores(i).Earned;
    temp2 = temp2 + scores(i).Worth;
    j = j + 1;
  
    if j == tot
        finalgrade = finalgrade + (temp1/temp2) * weight;
        temp1 = 0;
        temp2 = 0;
        j = 0;
    end
  
end
end

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