for_each for_each Category: algorithms Component type: function Prototype template <class InputIterator, class UnaryFunction> UnaryFunction for_each(InputIterator first, InputIterator last, UnaryFunction f); Description For_each applies the function object f to each element in the range [first, last); f's return value, if any, is ignored. Applications are performed in forward order, i.e. from first to last. For_each returns the function object after it has been applied to each element. [1] Definition Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h. Requirements on types InputIterator is a model of Input Iterator UnaryFunction is a model of Unary Function UnaryFunction does not apply any non-constant operation through its argument. InputIterator's value type is convertible to UnaryFunction's argument type. Preconditions [first, last) is a valid range. Complexity Linear. Exactly last - first applications of UnaryFunction. Example template<class T> struct print : public unary_function<T, void> { print(ostream& out) : os(out), count(0) {} void operator() (T x) { os << x << ' '; ++count; } 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 The function object overview, count, copy Copyright © 1999 Silicon Graphics, Inc. All Rights Reserved. TrademarkInformation