signbitf

Return a boolean indicating if the sign bit for a single-precision floating-point number is on (true) or off (false).

Usage

var signbitf = require( '@stdlib/number/float32/base/signbit' );

signbitf( x )

Returns a boolean indicating if the sign bit for a single-precision floating-point number is on (true) or off (false).

var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );

var bool = signbitf( toFloat32( 4.0 ) );
// returns false

bool = signbitf( toFloat32( -9.14e-34 ) );
// returns true

bool = signbitf( 0.0 );
// returns false

bool = signbitf( -0.0 );
// returns true

Examples

var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var randu = require( '@stdlib/random/base/randu' );
var signbitf = require( '@stdlib/number/float32/base/signbit' );

var sign;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = (randu()*100.0) - 50.0;
    x = toFloat32( x );
    sign = signbitf( x );
    sign = ( sign ) ? 'true' : 'false';
    console.log( 'x: %d. signbit: %s.', x, sign );
}

C APIs

Usage

#include "stdlib/number/float32/base/signbit.h"

stdlib_base_float32_signbit( x )

Returns an integer indicating whether the sign bit for a single-precision floating-point number is on (1) or off (0).

#include <stdint.h>

int8_t out = stdlib_base_float32_signbit( 3.14f );

The function accepts the following arguments:

x: [in] float input value.

int8_t stdlib_base_float32_signbit( const float x );

Examples

#include "stdlib/number/float32/base/signbit.h"
#include <stdint.h>
#include <stdio.h>
#include <inttypes.h>

int main( void ) {
    float x[] = { 3.14f, -3.14f, 0.0f, -0.0f, 4.0f, 1.0f, -1.0f, 1.0e38f, -1.0e38f };

    int8_t out;
    int i;
    for ( i = 0; i < 9; i++ ) {
        stdlib_base_float32_signbit( x[ i ], &out );
        printf( "%f => signbit: %" PRId8 "\n", x[ i ], out );
    }
}