Codecademy: Codeyear When Indexed Arrays Go Bad

//sample solution


//students actually in the class
var students = ["sharon","robert"];

//students on the roll
var roll = ["robert","joe","sharon"];

//the number of students present
var numPresent = 0;

//Write code that loops over every student in the students array.
//For each student, loop over every name in the roll array until
//you find the student's name.
//Whenever you find a student that is present, increment the numPresent
//counter by 1
for(var i=0; i<students.length; i++){
for(var j=0; j<roll.length; j++){
if(students[i]===roll[j]){
numPresent++;
}
}
}
console.log("The number of students present is "+numPresent+".");