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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Random Number Challenge Solution

Hamza Saleemi
Hamza Saleemi
4,257 Points
Posted by Hamza Saleemi
Hamza Saleemi
4,257 Points

Will it still work if upper is smaller than lower? and if so why?

if upper is smaller than lower then wouldn't it produce a negative value which can cause an error or a bug because the functionResult might not be in the required range. To compensate for this I used the following code:

function randomNum(first, second) {
  if (first > second){
    var upper = first;
    var lower = second;
  } else {
    var upper = second;
    var lower = first;
  }
  var functionResult = Math.floor(Math.random() * (upper - lower + 1)) + lower;
  return functionResult;
}

randomNum(10,20);
console.log(randomNum(10,20));

Now my solution seems to work as well, but what I can't understand is how does his solution work?

1 Answer

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

The original solution only works correctly if the numbers are entered in the proper order.

With a small number of tests, it might seem that it works either way,. But if you collected extensive statistics on it, you would discover that when the order is reversed, the random number generated will have a more limited range than intended.

Your mod generates in the proper range no matter what order the numbers are given. Good job. :+1:

Hamza Saleemi
Hamza Saleemi
4,257 Points
Hamza Saleemi
Hamza Saleemi
4,257 Points

Thanks! I kept scratching my brain for an hour trying to figure out how his method was working, but your explanation makes sense!