Practice 1

function practice1()
    clear;clc
    fprintf('Mustafa Kalash\nMATLAB Practice 1\n')

    fprintf('\nProblem 1\n')
    m = input('What is the upper bound of the summation?\nm = ');
    sigma = 0;
    for n = 0:m
        sigma = sigma + ((-1 / 3) ^ n) / (2 * n + 1);
    end
    answer = sqrt(12) * sigma;
    fprintf('The answer is %.2f.\n', answer)
    n = 0:3;
    answer = sqrt(12) * sum(((-1 / 3) .^ n) ./ (2 * n + 1));
    fprintf('The answer is %.2f.\n', answer)

    fprintf('\nProblem 2\n')
    cases = input('How many cases?\ncases = ');
    for n = 1:cases
        a = input('What is a?\na = ');
        b = input('What is b?\nb = ');
        c = input('What is c?\nc = ');
        D = b^2 - 4 * a * c;
        if D > 0
            rootOne = (-b + sqrt(D)) / (2 * a);
            rootTwo = (-b - sqrt(D)) / (2 * a);
            fprintf('The equation has two roots: %.2f, %.2f.\n', rootOne, rootTwo)
        elseif D == 0
            root = -b / (2 * a);
            fprintf('The equation has one root: %.2f.\n', root)
        else
            fprintf('The equation has no real roots.\n')
        end
    end

    % Problem 3
    Data = reshape((randi(87, 24)), 576, 1);
    divisableBy2 = 0;
    data = zeros(1, 7);
    for i = 1:length(Data)
        n = Data(i);
        if ~rem(n, 2)
            divisableBy2 = divisableBy2 + 1;
        end
        if n >= 0 && n < 15
            data(1) = data(1) + 1;
        elseif n >= 15 && n < 30
            data(2) = data(2) + 1;
        elseif n >= 30 && n < 45
            data(3) = data(3) + 1;
        elseif n >= 45 && n < 60
            data(4) = data(4) + 1;
        elseif n >= 60 && n < 75
            data(5) = data(5) + 1;
        elseif n >= 75 && n < 90
            data(6) = data(6) + 1;
        elseif n >= 90
            data(7) = data(7) + 1;
        end
    end
    figure1 = figure;
    axes1 = axes('Parent', figure1, 'XTickLabel', {'0-15', '15-30', '30-45', '45-60', '60-75', '75-90', '90+'}, 'XTick', 1:7);
    box(axes1, 'on')
    hold(axes1, 'on')
    bar(data)

    fprintf('\nProblem 4\n')
    n = input('How many numbers do you want to calculate?\nn = ');
    for i = 1:n
        fprintf('What is number %i?\n', i)
        m = input('m = ');
        fprintf('%.2f! = %.2f\n', m, calcFactorial(m));
    end

    fprintf('\nProblem 5\n')
    i = 1;
    while 1
        x = input('Enter the next value.\nx = ');
        if x >= 1
            a = input('Illegal value entered. Retry? (1 / 0)\n');
            if a
                continue
            else
                break
            end
        end
        y(i) = log(1/(1 - x));
        i = i + 1;
    end
    fprintf('y = ')
    fprintf('%.2f, ', y(1:length(y) - 1))
    fprintf('%.2f.\n', y(length(y)))
end

function fact = calcFactorial(n)
    if n < 0 || rem(n, 1) ~= 0
        error('Error: n must be a positive integer.')
    elseif n == 0
        fact = 1;
    else
        fact = n .* calcFactorial(n - 1);
    end
end