Not Sure Why I'm getting NaN on this code

Question

Trying to solve this ES6 Class Methods Practice Problem and this is my code so far:

You are making a program so that students are able to calculate their average of 3 exam scores.
The given program takes the scores of 3 exams as input and declares the Exams class.
Add a static method average() to class Exams, which will take the scores as parameters, and calculate and return the average score rounded to the nearest integer so that the code in main works correctly.

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1,exam2,exam3));
}
class Exams{
//your code goes here
constructor(x,y,z) {
this.x = x;
this.y = y;
this.z = z;
}
static average(a) {
const avg = ((a.x + a.y + a.z)/3);
return Math.round(avg);
};
};

I'm just a little confused as to why the function is returning NaN when I run it.

Answer 1

1. You don't need the constructor function.

2. Your average function only has one parameter - a - but Sololearn will call it with 3 arguments because there are 3 scores.

3. In your code, a.x, a.y, a.z will not work because that's like saying 20.x, 50.y, 70.z or something like that.

Answer 2

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1,exam2,exam3));

}
class Exams{
//your code goes here
static average (a, b, c) {
const avg = (a + b + c)/3;
return Math.round(avg);
};
};

Good Luck

Answer 3

It's a pro challenge, so i don't know if the constructor is already there. If it is, it is a red herring (you don't need it). The average method is static, so it is bound to the class and not an object of the class. Also because it is static you call it as Exams.average. It is supposed to take the 3 scores as parameters. That's why it is called like Exams.average(exam1, exam2, exam3) from main. Those are just 3 integers, no Exams object is created. The average method has to match that signature, so it has to take 3 parameters (integers) and return the average of those

Answer 4

Melanie Müller This is what my code looked like after I removed the constructor and fixed the average code accordingly

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1,exam2,exam3));

}
class Exams{
//your code goes here
static average (a, b, c) {
const avg = (a + b + c)/3;
return Math.round(avg);
};
};

Answer 5

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1,exam2,exam3));

}
class Exams{
//your code goes here
static average(exam1,exam2,exam3){
return Math.round((exam1+exam2+exam3)/3);

}
}

Answer 6

But what's the solution? I am at the same point.

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1,exam2,exam3));

}
class Exams{
//your code goes here
constructor(exam1,exam2,exam3){
this.exam1 = exam1
this.exam2 = exam2
this.exam3 = exam3
}

static average (a) {

return Math.round((a.exam1 + a.exam2 + a.exam3)/3);
}
}

Answer 7

Thank you guys. Know I understand my failure.

Answer 8

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1,exam2,exam3));

}
class Exams{
//your code goes here
static average (a, b, c) {
const avg = (a + b + c)/3;
return Math.round(avg);
};
};

Answer 9

Wher the given inpout for the exam goes?

Answer 10

function main() {
var exam1 = parseInt(readLine(), 10);
var exam2 = parseInt(readLine(), 10);
var exam3 = parseInt(readLine(), 10);

console.log(Exams.average(exam1, exam2, exam3));
}

class Exams {
static average(exam1, exam2, exam3) {
// Calculate the average and round it to the nearest integer
return Math.round((exam1 + exam2 + exam3) / 3);
}
}

Answer 11

when the object is passed as a parameter you can call it as a.x, a.y, a.z but here we just passing the variable so you can add it directly.

and why did you pass "a" as an parameter in our main method we are not creating any object and passing it to the average() static function

Answer 12

Your average function expects an Exams object but you are feeding it 3 integers