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Standard Template Library Programmer's Guide
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binary_negate<AdaptableBinaryPredicate>



Categories: functors, adaptors	Component type: type

Description

Binary_negate is a function object adaptor: it is an Adaptable Binary Predicate that represents the logical negation of some other Adaptable Binary Predicate. That is: if f is an object of class binary_negate<AdaptableBinaryPredicate>, then there exists an object pred of class AdaptableBinaryPredicate such that f(x,y) always returns the same value as !pred(x,y). There is rarely any reason to construct a binary_negate directly; it is almost always easier to use the helper function not2.

Example

Finds the first character in a string that is neither ' ' nor '\n'.

char str[MAXLEN];
...
const char* wptr = find_if(str, str + MAXLEN,
                           compose2(not2(logical_or<bool>()),
                                    bind2nd(equal_to<char>(), ' '),
                                    bind2nd(equal_to<char>(), '\n')));
assert(wptr == str + MAXLEN || !(*wptr == ' ' || *wptr == '\n'));

Definition

Defined in the standard header functional, and in the nonstandard backward-compatibility header function.h.

Template parameters

Parameter	Description	Default
`AdaptableBinaryPredicate`	The type of the function object that this `binary_negate` is the logical negation of.

Model of

Adaptable Binary Predicate

Type requirements

AdaptableBinaryPredicate must be a model of Adaptable Binary Predicate.

Public base classes

binary_function<AdaptableBinaryPredicate::first_argument_type,
                AdaptableBinaryPredicate::second_argument_type,
                bool>

Members

Member	Where defined	Description
`first_argument_type`	Adaptable Binary Function	The type of the first argument: `AdaptableBinaryPredicate::first_argument_type`
`second_argument_type`	Adaptable Binary Function	The type of the second argument: `AdaptableBinaryPredicate::second_argument_type`
`result_type`	Adaptable Binary Function	The type of the result: `bool`
binary_negate(const AdaptableBinaryPredicate& pred)	`binary_negate`	See below.
template <class AdaptableBinaryPredicate> binary_negate<AdaptableBinaryPredicate> not2(const AdaptableBinaryPredicate& pred);	`binary_negate`	See below.

New members

These members are not defined in the Adaptable Binary Predicate requirements, but are specific to binary_negate.

Member	Description
binary_negate(const AdaptableBinaryPredicate& pred)	The constructor. Creates a `binary_negate<AdaptableBinaryPredicate>` whose underlying predicate is `pred`.
template <class AdaptableBinaryPredicate> binary_negate<AdaptableBinaryPredicate> not2(const AdaptableBinaryPredicate& pred);	If `p` is of type `AdaptableBinaryPredicate` then `not2(p)` is equivalent to `binary_negate<AdaptableBinaryPredicate>(p)`, but more convenient. This is a global function, not a member function.