How to add 1 to the number using the "for" command when the number N is a function parameter?

Question

Being n the value of 5, adding up 1 + 2 + 3 + 4 + 5, resulting in the return.

I tried to do it like this, but it didn’t work:

function (n){

for ( var i = 0; i < n.length; i++ ){
   total += n[i];
}

return total;

Answer 1

I imagine you got some code ready that sweeps through a collection of data that sums up your values. Learning based on ready-made code is very popular, but it’s also the reason why people don’t understand what’s going on there, and programming is just understanding what’s going on.

So what you don’t want is to go through a collection, is to go through a numerical sequence, you don’t have to have a array how it was used. You just have to count without access to array some. And of course, you must accumulate the value in each step, as you did.

Nor would it be possible to catch the length of nbecause n it does not have a size, it is only a very simple number, who has size are data collections.

There are other errors. One of them is that it did not initialize the accumulator variable. It even works, but it is gambiarra.

Another is that the function has no name.

And finally can not start from 0, so described should start from 1 and go to the last number, inclusive. These errors are a consequence of using the idea of access to array that actually starts at 0 and ends at last number, uniquely.

function acumula(n) {
    var total = 0;
    for (var i = 1; i <= n; i++) total += i;
    return total;
}
console.log(acumula(5));

But you don’t need any of that, you can use pure mathematics and give the result without a tie.

function acumula(n) {
    return n * (n + 1) / 2;
}
console.log(acumula(5));

I put in the Github for future reference.