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JavaScript JavaScript Numbers The Math Object Random Number Challenge – Solution

Spencer Renfro
PLUS
Spencer Renfro
Courses Plus Student 11,133 Points
Posted by Spencer Renfro
Spencer Renfro
Courses Plus Student 11,133 Points

Math.floor vs. Math.ceil on random number generator

On the random number generator it uses Math.floor, but is there a reason for uses this specifically instead of Math.ceil?

1 Answer

jb30
jb30
44,805 Points
jb30
jb30
44,805 Points

Math.random() returns a number between 0 inclusive and 1 exclusive, which means that it can return 0 and cannot return 1. If you use Math.ceil(Math.random() * highValue) and Math.random() returns exactly 0, then you will have Math.ceil(0 * highValue), which is Math.ceil(0), which is 0, and 0 is not greater than or equal to 1.

Laisvūnas Miškinis
Laisvūnas Miškinis
6,614 Points

but why not use Math.round() in something like this:

let randomNum = Math.round(Math.random() * +maxValue);

you will no longer be forced to round only one way which will be more random than floor or ceil.