Clever Geek Handbook

Differences of random entire functions

while checking some code I found the following random number generator function:

function randomInt(min, max) {
    return min ? min : min = 0,
        max ? max : max = 1,
        0 | Math.random() * (max - min + 1) + min
}

Comparing it to the equivalent function on MDN :

// Returns a random integer between min (included) and max (excluded)
// Using Math.round() will give you a non-uniform distribution!
function getRandomInt(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

I understand that the first one creates and an integer with max

included and that it checks the values ​​or assigns default values ​​to them min

and max

, but I don't understand how it returns an integer and not a float without a method Math.floor()

.

Is this achieved with an expression 0 | Math.random() * (max - min + 1) + min

? If so, how?

+3


source to share


2 answers


The result is converted to an integer with an operator |

that is bitwise OR . From MDN, the first step in calculating the result:

Operands are converted to thirty-two bit integers and expressed as a series of bits (zeros and ones).



And since you are ORing from 0, this operation will not change the value of the result (other than the previously mentioned conversion).

+4


source


0 |

- bitwise operation.
It does not affect the value (ORing with a zero returns the original value), but like all bitwise operations, it truncates the integer (bitwise operations don't make sense for non-integers).



+1


source






More articles:


All Articles