function Fraction::subtract in Fraction 7

Subtract another fraction from this one.

Parameters

Fraction $fraction: Another fraction object to subtract this one.

Return value

Fraction Returns this Fraction object.

File

./fraction.class.inc, line 348

Fraction class

Class

Fraction

@file Fraction class

Code

function subtract(Fraction $fraction) {

  // Get the numerator and denominator of each fraction.
  $numerator1 = $this
    ->getNumerator();
  $denominator1 = $this
    ->getDenominator();
  $numerator2 = $fraction
    ->getNumerator();
  $denominator2 = $fraction
    ->getDenominator();

  // Calculate the difference of the two fractions.
  // Use BCMath if available.
  if (function_exists('bcmul') && function_exists('bcsub')) {
    $denominator = bcmul($denominator1, $denominator2, 0);
    $numerator = bcsub(bcmul($numerator1, $denominator2, 0), bcmul($numerator2, $denominator1, 0), 0);
  }
  else {
    $denominator = $denominator1 * $denominator2;
    $numerator = $numerator1 * $denominator2 - $numerator2 * $denominator1;
  }

  // Save the numerator and denominator.
  $this
    ->setNumerator($numerator);
  $this
    ->setDenominator($denominator);
  return $this;
}