CODEWITHSUNDEEP
javascriptfunctionintegerabsolute-value
chaneyz
chaneyz

Reputation: 95

How do I get the absolute value of an integer without using Math.abs?

How do I get the absolute value of a number without using math.abs?

This is what I have so far:

function absVal(integer) {
    var abs = integer * integer;
    return abs^2;
}

Upvotes: 5

Views: 13956

Answers (6)

Tony
Tony

Reputation: 2754

Late response, but I think this is what you were trying to accomplish:

function absVal(integer) {
   return (integer**2)**.5;
}

It squares the integer then takes the square root. It will eliminate the negative.

Upvotes: 3

Guffa
Guffa

Reputation: 700212

You can use the conditional operator and the unary negation operator:

function absVal(integer) {
  return integer < 0 ? -integer : integer;
}

Upvotes: 11

Satpal
Satpal

Reputation: 133403

You can also use >> (Sign-propagating right shift)

function absVal(integer) {
    return (integer ^ (integer >> 31)) - (integer >> 31);;
}

Note: this will work only with integer

Upvotes: 7

user4655509
user4655509

Reputation: 81

Check if the number is less than zero! If it is then mulitply it with -1;

Upvotes: 0

jdphenix
jdphenix

Reputation: 15415

There's no reason why we can't borrow Java's implementation. 

    function myabs(a) {
      return (a <= 0.0) ? 0.0 - a : a;
    }

    console.log(myabs(-9));

How this works:

  • if the given number is less than or zero
    • subtract the number from 0, which the result will always be > 0
  • else return the number (because it's > 0)

Upvotes: -1

newfurniturey
newfurniturey

Reputation: 38416

Since the absolute value of a number is "how far the number is from zero", a negative number can just be "flipped" positive (if you excuse my lack of mathematical terminology =P):

var abs = (integer < 0) ? (integer * -1) : integer;

Alternatively, though I haven't benchmarked it, it may be faster to subtract-from-zero instead of multiplying (i.e. 0 - integer).

Upvotes: 3

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