I think there are two problems with your code, first, your function is defined inside the while loop, so you can't get the function outside the body of the loop, and second, your loop does not change the loop, there should be a +1 operation in the loop, otherwise it is a dead loop

I don't know what you want to do with this code, maybe you can change your function, think about why the function definition is in the loop, and then optimize your code