function [selectedStudents] = selectstudents(totalStudents,varargin)
%selectstudents will randomly select students from a pre-defined list of
%students in the class. selectstudents requires one input argument: the
%number of students in the class and two optional input arguments: the
%number of students to select at random and a list of student ID numbers to
%exclude from the selection.
%
%selectstudents(28) will randomly select 1 student from a class of 28 students
%selectstudents(28,3) will randomly select 3 students
%selectstudents(28,3,[1 2 3]) will randomly select 3 students from the class
%and exclude the students with IDs 1,2, and 3
%
%The output of selectstudents will be an array of students and there ID
%numbers.  A row in the array will contain the ID number of the student in
%the first column and the name of the student in the second column
%Daniel Brateris

    %Define the list of students
    students = {'Kevin_A' 'Kenneth' 'Daniel' 'Timothy' 'Phillip' 'Adolfo' 'Jessica_M' 'Colin' 'Jessica_T' 'Trevor' 'Andrew' 'Brian' 'Michael_A' 'Allan' 'Brendan_R' 'Brendan_J' 'Richard_J' 'Wendell' 'David_M' 'Michael_S' 'Mohak' 'Kevin R.' 'Robert_W' 'Matthew' 'Richard_A' 'Eric' 'Robert_F' 'Christopher'};
    
    %Check to make sure totalStudents is <= the number of students in the array students
    if(totalStudents > size(students,2))
       errordlg('The number oif students must be less than 29');
       return
    end
    
    %Check for additional arguments and assign them to variables
    %Check for number of students to select
    if(size(varargin,2) >= 1)
        num2select = varargin{1};
    else
        num2select = 1;
    end
    
    %Check for  excluded students
    if(size(varargin,2) >= 2)
        excludedIDs = varargin{2};
    else
        excludedIDs = 0;
    end
    
    %Create an array for the selected students
    selectedStudents = zeros(0,2);
    %Create an array to hold previously choosen random numbers
    %used to ensure that a double selection does not occur
    previousRandomNumbers = [];
    
    %Reset the random number generator
    rand('twister',sum(100*clock))
    
    i = 0;
    while (i < num2select)
        %numberOK used to track if the random generated number was
        %previously generated by the randint function, initially assume OK
        numberOK = true;
        %Generate a random integer between 1 and total_students
        randomNumber = randint(1,1,[1,totalStudents]);
        %Check if the random number is one of the excluded ID's
        %if so, this is not a valid random number, set numberOK to false
        for j=1:length(excludedIDs)
            if (randomNumber == excludedIDs(j))
                numberOK = false;
            end
        end

        %Check if the random number has already been generated by randint
        %if so this in not a valid random number, set numberOK to false
        for j=1:length(previousRandomNumbers)
            if (randomNumber == previousRandomNumbers(j))
                numberOK = false;
            end
        end
        
        %Check if the random number is OK, if so add the corrosponding
        %student to the selected students list and increment the counter i
        %if the random number is OK add it to previousRandomNumbers
        if (numberOK)
            previousRandomNumbers = [previousRandomNumbers randomNumber];
            selectedStudents = [selectedStudents; randomNumber students(randomNumber)];
            i = i + 1;
        end
    end