transform

Prototype

template<
    class SinglePassRange1,
    class OutputIterator,
    class UnaryOperation
>
OutputIterator transform(const SinglePassRange1& rng,
                         OutputIterator out,
                         UnaryOperation fun);

template<
    class SinglePassRange1,
    class SinglePassRange2,
    class OutputIterator,
    class BinaryOperation
>
OutputIterator transform(const SinglePassRange1& rng1,
                         const SinglePassRange2& rng2,
                         OutputIterator out,
                         BinaryOperation fun);

Description

UnaryOperation version:

transform assigns the value y to each element [out, out + distance(rng)), y = fun(x) where x is the corresponding value to y in rng1. The return value is out + distance(rng).

BinaryOperation version:

transform assigns the value z to each element [out, out + min(distance(rng1), distance(rng2))), z = fun(x,y) where x is the corresponding value in rng1 and y is the corresponding value in rng2. This version of transform stops upon reaching either the end of rng1, or the end of rng2. Hence there isn't a requirement for distance(rng1) == distance(rng2) since there is a safe guaranteed behaviour, unlike with the iterator counterpart in the standard library.

The return value is out + min(distance(rng1), distance(rng2)).

Definition

Defined in the header file boost/range/algorithm/transform.hpp

Requirements

For the unary versions of transform:

SinglePassRange1 is a model of the Single Pass Range Concept.
OutputIterator is a model of the OutputIteratorConcept.
UnaryOperation is a model of the UnaryFunctionConcept.
SinglePassRange1's value type must be convertible to UnaryFunction's argument type.
UnaryFunction's result type must be convertible to a type in OutputIterator's set of value types.

For the binary versions of transform:

SinglePassRange1 is a model of the Single Pass Range Concept.
SinglePassRange2 is a model of the Single Pass Range Concept.
OutputIterator is a model of the OutputIteratorConcept.
BinaryOperation is a model of the BinaryFunctionConcept.
SinglePassRange1's value type must be convertible to BinaryFunction's first argument type.
SinglePassRange2's value type must be convertible to BinaryFunction's second argument type.
BinaryOperation's result type must be convertible to a type in OutputIterator's set of value types.

Precondition:

For the unary version of transform:

out is not an iterator within the range [begin(rng1) + 1, end(rng1)).
[out, out + distance(rng1)) is a valid range.

For the binary version of transform:

out is not an iterator within the range [begin(rng1) + 1, end(rng1)).
out is not an iterator within the range [begin(rng2) + 1, end(rng2)).
[out, out + min(distance(rng1), distance(rng2))) is a valid range.

Complexity

Linear. The operation is applied exactly distance(rng1) for the unary version and min(distance(rng1), distance(rng2)) for the binary version.