void letterB (const string &input, const College &college, const unordered_map<string, vector<Course>> &map) {
    double percentage;
    string gradingType;
    cout << "letter B threshold? ";
    cin >> percentage;

    vector<Course> coursePercentages;
    // perform a department wide search
    if (!(input == "all")) {

        if (map.find(input) == map.end()) {
            cout << "**dept not found\n";
            return;
        }

        // get the courses from the department
        vector<Course> deptCourses = map.at(input);

        // retrieve the courses in the specified department
        for (auto &c: deptCourses) {
            GradeStats stats = GetGradeDistribution(c);
            // if the percent of Bs are greater than the percentage entered, add to the vector
            if (stats.PercentB > percentage) {
                coursePercentages.push_back(c);
            }
        }
    }

    // perform a college-wide search
    else if (input == "all") {
        for (auto &d: college.Depts) {
            for (auto &c: d.Courses) {
                GradeStats stats = GetGradeDistribution(c);
                if (stats.PercentB > percentage) {
                    coursePercentages.push_back(c);
                }
            }
        }
    }

    // sort the B percentages vector by percentB > department > course number > section number
    sort(coursePercentages.begin(), coursePercentages.end(), [=] (Course &a, Course &b) {
        GradeStats aStats = GetGradeDistribution(a);
        GradeStats bStats = GetGradeDistribution(b);

        if ((fabs(aStats.PercentB) < fabs(bStats.PercentB) < .0001)) {
            return true;
        }
        else if ((fabs(aStats.PercentB) > fabs(bStats.PercentB) < .0001)) {
            return false;
        }
        else {
            if (a.Dept < b.Dept) {
                return true;
            }
            else if (a.Dept > b.Dept) {
                return false;
            }
            else {
                if (a.Number < b.Number) {
                    return true;
                }
                else if (a.Number > b.Number) {
                    return false;
                }
                else {
                    if (a.Section < b.Section) {
                        return true;
                    }
                    else {
                        return false;
                    }
                }
            }
        }
    });

    if (coursePercentages.empty()) {
        cout << "**none found\n";
        return;
    }

    for (auto &c: coursePercentages) {
        cout << c.Dept << " " << c.Number << " (section " << c.Section << "): " << c.Instructor << endl;
        cout << " # students: " << c.getNumStudents() << endl;


        // determine the grading type
        if (c.getGradingType() == 0) gradingType = "letter";
        else if (c.getGradingType() == 1) gradingType = "satisfactory";
        else if (c.getGradingType() == 2) gradingType = "unknown";

        cout << " course type: " << gradingType << endl;
        printDistribution(GetGradeDistribution(c));
        printDFW(c);

    }
    //printResults(coursePercentages);