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Function std.math.traits.isPowerOf2
Check whether a number is an integer power of two.
bool isPowerOf2(X)
(
const X x
) pure nothrow @nogc @safe
if (isNumeric!X);
Note that only positive numbers can be integer powers of two. This
function always return false
if x
is negative or zero.
Parameters
Name | Description |
---|---|
x | the number to test |
Returns
true
if x
is an integer power of two.
Example
import std .math .exponential : pow;
assert( isPowerOf2(1.0L));
assert( isPowerOf2(2.0L));
assert( isPowerOf2(0.5L));
assert( isPowerOf2(pow(2.0L, 96)));
assert( isPowerOf2(pow(2.0L, -77)));
assert(!isPowerOf2(-2.0L));
assert(!isPowerOf2(-0.5L));
assert(!isPowerOf2(0.0L));
assert(!isPowerOf2(4.315));
assert(!isPowerOf2(1.0L / 3.0L));
assert(!isPowerOf2(real .nan));
assert(!isPowerOf2(real .infinity));
Example
assert( isPowerOf2(1));
assert( isPowerOf2(2));
assert( isPowerOf2(1uL << 63));
assert(!isPowerOf2(-4));
assert(!isPowerOf2(0));
assert(!isPowerOf2(1337u));
Authors
Walter Bright, Don Clugston, Conversion of CEPHES math library to D by Iain Buclaw and David Nadlinger
License
Copyright © 1999-2022 by the D Language Foundation | Page generated by ddox.