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

Evaluates the integer quotient Number1 // Number2 and unifies the resulting value with Result.
Number1
Integer.
Number2
Integer.
Result
Output: integer.

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.

This division operates on integer arguments, and delivers an integer result rounded towards zero (truncated). The corresponding remainder is computed by the rem operation, such that the following equivalence always holds:

X =:= (X rem Y) + (X // Y) * Y.
The relationship with floating-point division is:
X // Y =:= integer(truncate(X/Y)).

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
Number1 or Number2 is a number but not an integer.
(24) number expected
Number1 or Number2 is not of a numeric type.
(20) arithmetic exception
Illegal arithmetic operation: division by 0

Examples

Success:
X is  10 //  3.		% gives X =  3
X is -10 //  3.		% gives X = -3
X is  10 // -3.		% gives X = -3
X is -10 // -3.		% gives X =  3

Error:
X is 2//0.			% arithmetic exception