for_each
Prototypetemplate <class InputIterator, class UnaryFunction>
UnaryFunction for_each(InputIterator first, InputIterator last, UnaryFunction f);
Description
DefinitionDefined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h. Requirements on types
Preconditions
ComplexityLinear. Exactly Exampletemplate<class T> struct print : public unary_function<T, void>
{
print(ostream& out) : os(out), count(0) {}
ostream& os;
int count;
};
int main()
{
int A[] = {1, 4, 2, 8, 5, 7};
const int N = sizeof(A) / sizeof(int);
print<int> P = for_each(A, A + N, print<int>(cout));
cout << endl << P.count << " objects printed." << endl;
}
Notes[1] This return value is sometimes useful, since a function object may have local state. It might, for example, count the number of times that it is called, or it might have a status flag to indicate whether or not a call succeeded. See also |