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

Posted by Christopher Sea
Christopher Sea
3,726 Points

Not sure what I'm doing wrong.

When I try this:

function getRandomNumber(upper, lower) {
    return Math.floor(Math.random() * (upper - lower + 1)) + lower;
}
console.log(getRandomNumber(100, 1));

it works properly.

When I try this:

var lowNum = prompt('Please choose a number.');
var highNum = prompt('Please choose a number larger than ' + lowNum + '.');

function getRandomNumber(upper, lower) {
    return Math.floor(Math.random() * (upper - lower + 1)) + lower;
}
console.log(getRandomNumber(highNum, lowNum));

it does not.

There is no error message in the console, but a number outside the given range appears.

1 Answer

Ryan S
Ryan S
27,276 Points
Ryan S
Ryan S
27,276 Points

Hey Christopher,

The issue is that the prompt() function will always return a string. So whatever numbers you give it will actually be strings and I think that is causing strange things to happen in your getRandomNumber() function.

If you use parseInt() to convert them into integers then it should solve your problem:

var lowNum = parseInt(prompt('Please choose a number.'));
var highNum = parseInt(prompt('Please choose a number larger than ' + lowNum + '.'));
Christopher Sea
Christopher Sea
3,726 Points

Thank you.