Program not printing to a text file properly

read = importdata("testscores.txt");

StudentID = read(:,1);
Score = read(:,2);
fid = fopen('FinalGrades.txt', 'w');

FinalGrades = read(:,2);
LowScore = min(FinalGrades);
HighScore = max(FinalGrades);
AverageScore = mean(FinalGrades);
StandardDeviation = std(FinalGrades);
TotalA = 0;
TotalB = 0;
TotalC = 0;
TotalD = 0;
TotalF = 0;

fprintf("Here is a summary of all the scores \n")
fprintf("The lowest score in the class was a %0.1f. \n", LowScore)
fprintf("The highest score in the class was a %0.1f\n", HighScore)
fprintf("The average score of the entire class was %0.1f \n", AverageScore)
fprintf("The standard deviation of all the scores was %0.3f \n", StandardDeviation)

StudentID = read(1);
Score = read(2);

Grades = cell(size(Score));
for i = 1:numel(Score);
   if Score(i) >= AverageScore + 1.5 * StandardDeviation
       Grades{i} = 'A';
   elseif Score(i) >= AverageScore + 0.5 * StandardDeviation
        Grades{i} = 'B';
   elseif Score(i) >= AverageScore - 0.5 * StandardDeviation
       Grades{i} = 'C';
   elseif Score(i) >= AverageScore - 1.5 * StandardDeviation
        Grades{i} = 'D';
   else
        Grades{i} = 'F';
   end
end

fid=fopen("FinalGrades.txt", "w");

for i = 1:numel(StudentID);
    fprintf(fid, '%d\t%s\n', StudentID(i), Grades{i});
end

I have this code, which is supposed to read a bunch of data from a .txt file, then determine which student by student ID got what letter grade. It seems to work fine up until the point where I need it to print the table of Student IDs and letter grades to a new text file. When that occurs, it only prints one line of 1 student ID and 1 letter grade. Not sure what is going wrong.

Answer 1

[Voss]

At first you make StudentID and Score column vectors

StudentID = read(:,1);
Score = read(:,2);

and later you overwrite those to be scalars

StudentID = read(1);
Score = read(2);

That's why it's only outputting a single ID and grade. Remove the second definition and stick with the first.

Also, you're opening the file with fopen two times. Just open it once, and don't forget to fclose it when you're done.