getbit(+Number, +Index, -Result)

-Result is getbit(+Number, +Index)

Number

Integer.

Index

Non-negative integer.

Result

Output: integer.

Description

This predicate can be used as a function in arithmetic expressions. In coroutining mode, if Number or Index are uninstantiated, the call is delayed until these variables are instantiated.

Modes and Determinism

• getbit(+, +, -) is det

Exceptions

(4) instantiation fault

Number or Index is not instantiated (non-coroutining mode only).

(5) type error

Number or Index is a number but not an integer.

(24) number expected

Number or Index is not of a numeric type.

Examples

    % 10 is binary 1010
    Result is getbit(10, 3).		% gives Result = 1.
    Result is getbit(10, 2).		% gives Result = 0.
    Result is getbit(10, 99).		% gives Result = 0.

    % Test for a 1-bit:
    getbit(10, 3, 1)                    % succeeds
    getbit(10, 2, 1)                    % fails

    % Test for a 0-bit:
    getbit(10, 3, 0)                    % fails
    getbit(10, 2, 0)                    % succeeds

See Also