Tell us what’s happening:
Describe your issue in detail here.
I dont understand this line of code mean:
let num = rangeOfNumbers(startNum, endNum - 1);

What is num value now? is it a function? for example endNum is 3 and startNum is 0 now num is rangeOfNumbers(0, 2);?

if yes what does that mean? a variable that become a function i am confuse about that.

``````  **Your code so far**
``````
``````
function rangeOfNumbers(startNum, endNum)
{
if (endNum - startNum === 0)
{
return [startNum];
}
else
{
let num = rangeOfNumbers(startNum, endNum - 1);
num.push(endNum);
return num;

}

};
``````
``````  **Your browser information:**
``````

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Challenge: Use Recursion to Create a Range of Numbers

This line of code

`let num = rangeOfNumbers(startNum, endNum - 1);`

assigns the value returned from `rangeOfNumbers(startNum, endNum - 1)` to the variable `num`.

So after that statement executes, the variable ` num` contains whatever has been returned from the `rangeOfNumbers` function.

a little more clear thank you. But i unclear on:
`assigns the value returned from *rangeOfNumbers(startNum, endNum - 1)* to the variable num.`

for example: startNum = 0 ; endNum = 2;
`now become let num = rangeOfNumbers(0, 1);`
how a `rangeOfNumbers(0, 1); can use push *num.push(endNum);*` ?

Because as it works through that function, it first gets to rangeOfNumbers and has to stop at that line to evaluate that recursive call, so it starts a function call, then it gets to the line with rangeOfNumbers, has to evaluate that recursive call, so it starts a function call, then it gets to the line with rangeOfNumbers… it keeps doing that until it has a function call that can finish, when `endNum - startNum === 0`, then it can finally finish a function call and it returns an array, after that, they incomplete function calls cascade finish, returning the array each time, so that push line will always have an array.

I think a big part of understanding recursion is understanding how the call stack works, even in just a qualitative sense. Put in a bunch of log statements and see in what order different lines get called. Or search the forum - there are A LOT of threads discussing this, some with detailed explanations.

And remember that recursion is a confusing subject, so don’t get frustrated. You shouldn’t expect to understand it right away.

From the instructions

The function should return an array of integers

So, the `rangeOfNumbers(startNum, endNum - 1)` function returns an array.
In the code that you posted, that array is stored in the variable `num`.

And, as `push()` is an array method, it can be used to modify the array in the `num` variable.

Personally, I’d choose a different name for that variable - `newArray` perhaps? - as I think the variable name might be confusing you.

In this forum post, @lasjorg posted a link to a Visualizer that might help you understand what’s happening in the recursion.

thank you i will see some more post from thread.

Yeah maybe that also confusing me too.Thanks for pointing that out,will check that forum too.

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