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

# /(+Number1, +Number2, -Result)

Evaluates the quotient Number1 / Number2 and unifies the resulting value with Result.
Number1
A number.
Number2
A number.
Result
A variable or float (resp. rational).

## Description

This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to /(Number1, Number2, Result) is equivalent to
```    Result is Number1 / Number2
```
which should be preferred for portability.

The result type of the division depends on the value of the global flag prefer_rationals. When it is off, the result is a float, when it is on, the result is a rational. In coroutining mode, if Number1 or Number2 are uninstantiated, the call to //3 is delayed until these variables are instantiated.

### Modes and Determinism

• /(+, +, -) is det

### Exceptions

(4) instantiation fault
Number1 or Number2 is not instantiated (non-coroutining mode only).
(5) type error
Result is a number but not a float (resp. rational).
(24) number expected
Number1 or Number2 is not of a numeric type.
(24) number expected
Result is neither a number nor a variable.
(20) arithmetic exception
Illegal arithmetic operation: division by 0

## Examples

```Success:
/(10, 2, 5.0).
/(10, -2.0, -5.0).
/(9, 12, 3_4).      (with set_flag(prefer_rationals, on))
Fail:
/(1, 2, 1.0).
Error:
/(A, 2, 6.0).            (Error 4).
/(5, 2, r).              (Error 5).
/(6, 2, 3).              (Error 5).
/(2, 0, Result).         (Error 20).
/(4 + 2, 2, 12).         (Error 24).

```