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

-Result is +Number1 // +Number2

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

Description

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

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)).

This predicate can be used as a function in arithmetic expressions. In coroutining mode, if Number1 or Number2 are uninstantiated, the call to (//)/3 is delayed until these variables are instantiated.

Modes and Determinism

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

See Also

is / 2, div / 3, rem / 3