Standard Template Library Programmer's Guide

pointer_to_unary_function , ptr_fun , Adaptable Binary Function

Categories: functors, adaptors

Component type: type

Unary_negate is a function object adaptor: it is an Adaptable Predicate that represents the logical negation of some other Adaptable Predicate. That is: if f is an object of class unary_negate , then there exists an object pred of class AdaptablePredicate such that f(x) always returns the same value as !pred(x) . [1] There is rarely any reason to construct a unary_negate directly; it is almost always easier to use the helper function not1 .

Finds the first element in a list that does not lie in the range from 1 to 10.

list L;

…

list::iterator in_range = find_if(L.begin(), L.end(), not1(compose2(logical_and(), bind2nd(greater_equal(), 1), bind2nd(less_equal(), 10))));

assert(in_range == L.end() || !(*in_range >= 1 && *in_range <= 10));

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

Adaptable Predicate

AdaptablePredicate must be a model of Adaptable Predicate.

unary_function

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

[1] Strictly speaking, unary_negate is redundant. It can be constructed using the function object logical_not and the adaptor unary_compose .

The function object overview, Adaptable Predicate, Predicate, binary_negate , unary_compose , binary_compose

Categories: functors, adaptors

Component type: type

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 , 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 .

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()), bind2nd(equal_to(), ' '), bind2nd(equal_to(), '\n')));

assert(wptr == str + MAXLEN || !(*wptr == ' ' || *wptr == '\n'));

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

Adaptable Binary Predicate

AdaptableBinaryPredicate must be a model of Adaptable Binary Predicate.

binary_function

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

The function object overview, AdaptablePredicate, Predicate, unary_negate , unary_compose , binary_compose