Function Object
Unary function object that returns the negation of its argument.
#include <functional> template <class T> struct negate : public unary_function<T, T>;
negate is a unary function object. Its operator() returns the negation of its argument, i.e., true if its argument is false, or false if its arguement is true. You can pass a negate object to any algorithm that requires a unary function. For example, the transform algorithm applies a unary operation to the values in a collection and stores the result. negate could be used in that algorithm in the following manner:
vector<int> vec1; vector<int> vecResult; . . . transform(vec1.begin(), vec1.end(), vecResult.begin(), negate<int>());
After this call to transform, vecResult(n) will contain the negation of the element in vec1(n).
template <class T>
struct negate : unary_function<T, T> { typedef typename unary_function<T,T>::argument_type argument_type; typedef typename unary_function<T,T>::result_type result_type; T operator() (const T&) const; };
If your compiler does not support default template parameters, then you need to always supply the Allocator template argument. For instance, you will need to write :
vector<int, allocator>
instead of :
vector<int>
Function Objects, unary_function