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# Exponent

> Return an integer corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].

<section class="usage">

## Usage

```javascript
var exponent = require( '@stdlib/number/float64/base/exponent' );
```

#### exponent( x )

Returns an `integer` corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].

```javascript
var exp = exponent( 3.14e307 ); // => 2**1021 ~ 1e307
// returns 1021

exp = exponent( 3.14e-307 ); // => 2**-1019 ~ 1e-307
// returns -1019

exp = exponent( -3.14 );
// returns 1

exp = exponent( 0.0 );
// returns -1023

exp = exponent( NaN );
// returns 1024
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var pow = require( '@stdlib/math/base/special/pow' );
var exponent = require( '@stdlib/number/float64/base/exponent' );

var frac;
var exp;
var x;
var e;
var i;

// Generate random numbers and extract their exponents...
for ( i = 0; i < 100; i++ ) {
    frac = randu() * 10.0;
    exp = round( randu()*646.0 ) - 323;
    x = frac * pow( 10.0, exp );
    e = exponent( x );
    console.log( 'x: %d. unbiased exponent: %d.', x, e );
}
```

</section>

<!-- /.examples -->

<section class="links">

[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985

</section>

<!-- /.links -->