isEven

Test if a finite numeric value is an even number.

Usage

var isEven = require( '@stdlib/math/base/assert/is-even' );

isEven( x )

Tests if a finite numeric value is an even number.

var bool = isEven( 5.0 );
// returns false

bool = isEven( -2.0 );
// returns true

bool = isEven( 0.0 );
// returns true

bool = isEven( NaN );
// returns false

Notes

The function assumes a finite number. If provided positive or negative infinity, the function will return true, when, in fact, the result is undefined. If x can be infinite, wrap the implementation as follows:

function check( x ) {
    return (
        x < Infinity &&
        x > -Infinity &&
        isEven( x )
    );
}

var bool = check( Infinity );
// returns false

bool = check( -Infinity );
// returns false

Examples

var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var isEven = require( '@stdlib/math/base/assert/is-even' );

var bool;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    x = round( randu()*100.0 );
    bool = isEven( x );
    console.log( '%d is %s', x, ( bool ) ? 'even' : 'not even' );
}

C APIs

Usage

#include "stdlib/math/base/assert/is_even.h"

stdlib_base_is_even( x )

Tests if a finite numeric value is an even number.

bool out = stdlib_base_is_even( 1.0 );
// returns false

out = stdlib_base_is_even( 4.0 );
// returns true

The function accepts the following arguments:

x: [in] double input value.

bool stdlib_base_is_even( const double x );

Examples

#include "stdlib/math/base/assert/is_even.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

int main( void ) {
    double x;
    bool v;
    int i;
    
    for ( i = 0; i < 100; i++ ) {
        x = ( ( (double)rand() / (double)RAND_MAX ) * 100.0 );
        v = stdlib_base_is_even( x );
        printf( "x = %lf, is_even(x) = %s\n", x, ( v ) ? "even" : "not even" );
    }
}