
Hosted by 


binder1st<AdaptableBinaryFunction>




Categories: functors, adaptors 
Component type: type 
Description
Binder1st is a function object adaptor: it is used to transform
an adaptable binary function into an adaptable unary function.
Specifically, if f is an object of class
binder1st<AdaptableBinaryFunction>, then f(x) returns
F(c, x), where F is an object of class AdaptableBinaryFunction
and where c is a constant. Both F and c are passed as arguments to
binder1st's constructor. [1]
The easiest way to create a binder1st is not to call the constructor
explicitly, but instead to use the helper function bind1st.
Example
Finds the first nonzero element in a list.
list<int> L;
...
list<int>::iterator first_nonzero =
find_if(L.begin(), L.end(), bind1st(not_equal_to<int>(), 0));
assert(first_nonzero == L.end()  *first_nonzero != 0);
Definition
Defined in the standard header functional, and in the nonstandard
backwardcompatibility header function.h.
Template parameters
Parameter

Description

Default

AdaptableBinaryFunction

The type of the binary function whose first argument is being bound
to a constant.


Model of
Adaptable Unary Function
Type requirements
AdaptableBinaryFunction must be a model of Adaptable Binary Function.
Public base classes
unary_function<AdaptableBinaryFunction::second_argument_type,
AdaptableBinaryFunction::result_type>
Members
Member

Where defined

Description

argument_type

Adaptable Unary Function

The type of the function object's argument, which is
AdaptableBinaryFunction::second_argument_type

result_type

Adaptable Unary Function

The type of the result: AdaptableBinaryFunction::result_type

result_type operator()(const argument_type& x) const

Adaptable Unary Function

Function call. Returns F(c, x), where F and c are the
arguments with which this binder1st was constructed.

binder1st(const AdaptableBinaryFunction& F,
AdaptableBinaryFunction::first_argument_type c)

binder1st

See below

template <class AdaptableBinaryFunction, class T>
binder1st<AdaptableBinaryFunction>
bind1st(const AdaptableBinaryFunction& F, const T& c);

binder1st

See below

New members
These members are not defined in the
Adaptable Unary Function
requirements, but are specific to
binder1st.
Member

Description

binder1st(const AdaptableBinaryFunction& F,
AdaptableBinaryFunction::first_argument_type c)

The constructor. Creates a binder1st such that calling it with
the argument x (where x is of type
AdaptableBinaryFunction::second_argument_type) corresponds to the
call F(c, x).

template <class AdaptableBinaryFunction, class T>
binder1st<AdaptableBinaryFunction>
bind1st(const AdaptableBinaryFunction& F, const T& c);

If F is an object of type AdaptableBinaryFunction,
then bind1st(F, c) is equivalent to
binder1st<AdaptableBinaryFunction>(F, c), but is more convenient.
The type T must be convertible to
AdaptableBinaryFunction::first_argument_type. This is a global
function, not a member function.

Notes
[1]
Intuitively, you can think of this operation as "binding" the
first argument of a binary function to a constant, thus yielding
a unary function. This is a special case of a closure.
See also
The function object overview, binder2nd,
Adaptable Unary Function, Adaptable Binary Function
STL Main Page