equal_to

Category: functors		Component type: type

Description

Equal_to<T> is a functors. Specifically, it is an AdaptableBinaryPredicate, which means it is a function object that tests the truth or falsehood of some condition. If f is an object of class equal_to<T> and x and y are objects of class T, then f(x,y) returns true if x == y and false otherwise.

Example

Rearrange a vector such that all of the elements that are equal to zero precede all nonzero elements.

Vector<int> V;
...
partition(V.begin(), V.end(), bind2nd(equal_to<int>(), 0));

Definition

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

Template parameters

Parameter	Description	Default
T	The type of equal_to's arguments.

Model of

AdaptableBinaryPredicate, DefaultConstructible

Type requirements

T is EqualityComparable.

Public base classes

binary_function<T, T, bool>.

Members

Member	Where defined	Description
first_argument_type	AdaptableBinaryPredicate	The type of the first argument: T
second_argument_type	AdaptableBinaryPredicate	The type of the second argument: T
result_type	AdaptableBinaryPredicate	The type of the result: bool
equal_to()	DefaultConstructible	The default constructor.
bool operator()(const T& x, const T& y)	BinaryFunction	Function call operator. The return value is x == y.

New members

All of equal_to's members are defined in the AdaptableBinaryPredicate and DefaultConstructible requirements. Equal_to does not introduce any new members.

Notes

See also

The functors, AdaptableBinaryPredicate, not_equal_to, greater, less, greater_equal, less_equal