Memory & arrays - Gradebook Program

#include <iostream>
#include <iomanip>
#include <cstdlib>

using namespace std;

string fn[9];
string ln[9];
double grades[9][5];
int records = 0;
int width = 0;
int lengths[9];
int longest;
int gradecount = 0;

int findlongestname()
{
    for (int i = 0; i < 9; i++)
    {
        lengths[i] = ln[i].length() + fn[i].length() + 6;

        if (lengths[i] > lengths[i - 1])
        {
            longest = lengths[i];
        }
    }

    if (longest < 14)
    {
        longest = 14;
    }

    return longest;
}

void viewgradebook()
{

    width = findlongestname();

    cout << left << setw(width) << "Student";

    for (int i = 0; i < 5; i++)
    {
        cout << right << setw(5) << i + 1;
    }

    cout << setw(0) << endl;

    for (int i = 0; i < 9; i++)
    {

        cout << i + 1 << ". ";

        if (ln[i] == "")
        {
            cout << left << setw(width + 1) << "N/A";
        }

        else
        {
            cout << left << setw(ln[i].length()) << ln[i] << setw(2) << ", " << setw(width - ln[i].length() - 1) << fn[i];
        }


        for (int j = 0; j < 5; j++)
        {
            cout << setw(5) << grades[i][j];
        }

        cout << endl;
    }

    cout << endl;
}

void addstudent()
{
    cout << "Enter the student's last name: ";
    cin >> ln[records];
    cout << "Enter the student's first name: ";
    cin >> fn[records];

    records++;

    cout << endl;
}

void delstudent()
{

}

void newgrade()
{
    int pointspossible;
    int pointsearned[9];

    cout << "How many total points were possible for this assignment? ";
    cin >> pointspossible;

    for (int i = 0; i < 9; i++)
    {
        if (ln[i] != "")
        {
            cout << "Enter " << fn[i] << " " << ln[i] << "'s points earned: ";
            cin >> pointsearned[i];
        }

        grades[i][gradecount] = pointsearned[i] / pointspossible;
    }
    gradecount++;

}

int main()
{

    bool running = true;

    while (running)
    {

        int menuchoice;

        cout << "What would you like to do? (Enter number of selection)";
        cout << "\n1. View Gradebook\n2. Enter New Student\n3. Delete Student\n4. Enter New Grade\n\n";

        cout << "Selection: ";
        cin >> menuchoice;

        cout << endl;

        if (menuchoice == 1)
        {
            viewgradebook();
        }
        else if (menuchoice == 2)
        {
            addstudent();
        }
        else if (menuchoice == 3)
        {
            delstudent();
        }
        else if (menuchoice == 4)
        {
            newgrade();
        }

    }

}