# exponentf
> Return an integer corresponding to the unbiased exponent of a [single-precision floating-point number][ieee754].
## Usage
```javascript
var exponentf = require( '@stdlib/number/float32/base/exponent' );
```
#### exponentf( x )
Returns an integer corresponding to the unbiased exponent of a [single-precision floating-point number][ieee754].
```javascript
var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var exp = exponentf( toFloat32( 3.14e34 ) ); // => 2^114 ~ 2.08e34
// returns 114
exp = exponentf( toFloat32( 3.14e-34 ) ); // => 2^-112 ~ 1.93e-34
// returns -112
exp = exponentf( toFloat32( -3.14 ) );
// returns 1
exp = exponentf( 0.0 );
// returns -127
exp = exponentf( NaN );
// returns 128
```
## Examples
```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 toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var exponentf = require( '@stdlib/number/float32/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()*44.0 ) - 22;
x = frac * pow( 10.0, exp );
x = toFloat32( x );
e = exponentf( x );
console.log( 'x: %d. unbiased exponent: %d.', x, e );
}
```
* * *
## C APIs
### Usage
```c
#include "stdlib/number/float32/base/exponent.h"
```
#### stdlib_base_float32_exponent( x )
Returns an integer corresponding to the unbiased exponent of a [single-precision floating-point number][ieee754].
```c
#include
int32_t out = stdlib_base_float32_exponent( 3.14f );
```
The function accepts the following arguments:
- **x**: `[in] float` input value.
```c
int32_t stdlib_base_float32_exponent( const float x );
```
### Examples
```c
#include "stdlib/number/float32/base/exponent.h"
#include
#include
#include
int main( void ) {
float x[] = { 4.0f, 0.0f, -0.0f, 1.0f, -1.0f, 3.14f, -3.14f, 1.0e38f, -1.0e38f, 1.0f/0.0f, -1.0f/0.0f, 0.0f/0.0f };
int32_t out;
int i;
for ( i = 0; i < 12; i++ ) {
out = stdlib_base_float32_exponent( x[ i ] );
printf( "%f => out: %" PRId32 "\n", x[ i ], out );
}
}
```
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
[@stdlib/number/float64/base/exponent]: https://github.com/stdlib-js/number/tree/main/float64/base/exponent