كيف تم تعريف مصفوفة بداخل الدالة و كيف تم التعامل معها بحلقة؟

function printAvg(arr)
{
    var avg;
    var s = 0;
    
    for (var i=0; i<arr.length; i++)
    {
        s = s + arr[i];
    }
    
    avg = s / arr.length;
    
    write("Your average is: " + avg + "\n");
    
    if (avg >= 10 && avg <= 20)
    {
        write("Congratulations you have succeeded.")
    }
    else if (avg >= 0 && avg <10)
    {
        write("Sorry you failed.")
    }
    else
    {
        write("Something wrong, impossible reuslt!");
    }
}


methods = ["Algorithms", "Java", "Databases", "Linux", "Networks"];
notes = array(methods.length);

for (var i=0; i<methods.length; i++)
{
    do
    {
        write(methods[i] + ": ");
        notes[i] = read();
    }
    while (notes[i] < 0 || notes[i] > 20 || isNaN(notes[i]));
}

write("---------------\n");

printAvg(notes);

Algorithms: 18
Java: 14
Databases: 10
Linux: 6
Networks: 15
---------------
Your average is: 12.6
Congratulations you have succeeded.