What Java method takes an int and returns +1 or -1?

Question

What Java method takes an int and returns +1 or -1? The criteria for this is whether or not the int is positive or negative. I looked through the docum

Answer 1

Math.signum(double i)

Returns the signum function of the argument; zero if the argument is zero, 1.0 if the argument is greater than zero, -1.0 if the argument is less than zero. Special Cases:

• If the argument is NaN, then the result is NaN.
• If the argument is positive zero or negative zero, then the result is the same as the argument.

Parameters:

• d - the floating-point value whose signum is to be returned

Returns: The signum function of the argument

Since: 1.5

Answer 2

Integer.signum(int i)

Answer 3

Math.signum(value) will do the trick but since it returns float or double (according to parameter) you will have to cast it:

int sign = (int)Math.signum(value);

or:

Integer.signum(value);

Answer 4

Strictly evaluating to -1 or 1, and cooler (probably more efficient too) than n < 0 ? -1: 1:

(n >> 31) | 1

In case you want to use it for long too:

(n >> 63) | 1

Answer 5

Use Integer.signum(int i), but if you want a custom in-line bit of code:

int ans = i < 0 ? -1 : 1;

if you want 0 also:

int ans = i == 0 ? 0 : (i < 0 ? -1 : 1);

Answer 6

For fun:

return (i > 0) ? 1 : ( (i < 0) ? -1 : 0 );