Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops What are Loops?

Posted by ammarkhan
.a{fill-rule:evenodd;}techdegree
ammarkhan
Front End Web Development Techdegree Student 21,661 Points

understanding RandomNumber function

So, i was trying to understand the code for function in the movie and end up doing this 

function RandomNumber(upper){
    return Math.random(Math.floor(upper) + 1);
}

and it worked. Now i am trying to understand why did this work and why my numbers are in decimals?

1 Answer

Steven Parker
Steven Parker
231,268 Points
Steven Parker
Steven Parker
231,268 Points

:point_right: Math.random doesn't take an argument.

Providing one does not cause an error, but it is ignored. So your function is equavalent to: "Math.random()". And by itself, that returns decimal numbers less than 1.

If you wanted a function to return random integers chosen from a set going from 1 to a specified upper limit, you could write it this way:

function RandomNumber(upper) {
    return Math.floor(Math.random() * upper) + 1;
}