[ Arithmetic | The ECLiPSe Built-In Predicates | Reference Manual | Alphabetic Index ]

# denominator(+Number, -Result)

Extracts the denominator of the rational Number and unifies the resulting integer with Result.

Number
  An integer or rational number.
Result
  A variable or integer.

## Description

This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to denominator(Number, Result) is equivalent to

        Result is denominator(Number)

which should be preferred.

In coroutining mode, if Number is uninstantiated, the call to denominator/2 is delayed until this variable is instantiated.

### Modes and Determinism

- denominator(+, -) is det

### Exceptions

(4) instantiation fault
  Number is not instantiated (non-coroutining mode only).
(5) type error
  Number is a float or breal.
(5) type error
  Result is a number but not an integer.
(24) number expected
  Number is not of a numeric type.
(24) number expected
  Result is neither a number nor a variable.

## Examples

    Success:
          denominator(3_4, 4).
          denominator(9_12, 4).
          denominator(-3_4, 4).
          denominator(25, 1).
    Fail:
          denominator(3_4, 3).
    Error:
          denominator(A, 3).                     (Error 4).
          denominator(3.1, 3).                   (Error 5).
          denominator(3_4, 3_1).                 (Error 5).
          denominator(3_4, r).                   (Error 24).
          denominator(1_3 + 3_4, 12).            (Error 24).

## See Also

is / 2, numerator / 2, rational / 2