Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

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
210,423 Points
Steven Parker
Steven Parker
210,423 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;
}