Standard Template Library Programmer's Guide

This difference has two implications. First, sequence_buffer is only useful if appending an array of N elements is much more efficient than inserting a single element N times. Second, sequence_buffer assumes that it can insert elements at the end of a container using an append member function. This member function is not part of the Container or Sequence requirements. The sequence_buffer adaptor can be used with rope , but not with any of the other containers in the library. (This is the reason why sequence_buffer is defined in the file rope.h, instead of in iterator.h.)

If you want to build up a string one character at a time, it is much more efficient to use sequence_buffer than to repeatedly add single characters to the end of a rope .

int main() {

const char* const s = "this is a test";

const int N = strlen(s);

crope r;

transform(s, s + N, sequence_buffer(r), toupper);

cout << "r = " << r << endl;

}

Defined in the header rope, and in the backward-compatibility header rope.h. The sequence_buffer class, and the rope header, are SGI extensions; they are not part of the C++ standard.

Output Iterator.

• Container is a variable-sized Forward Container

• Container 's value type T is a model of Default Constructible, as well as Assignable.

• Container has a member function that appends a range. Specifically: If x is an object of type Container and f and l are of type T* , then x.append(f, l) appends the range [f, l) to x . [1]

output_iterator

These members are not defined in the Output Iterator requirements, but are specific to sequence_buffer .

[1] Despite the name "sequence_buffer", this adaptor cannot actually be used with arbitrary sequences: it requires that the template argument Container have an append member function that can insert multiple elements at the end of the container. This member function is not part of the Sequence requirements. This means that sequence_buffer can be used with rope , but not with any of the other predefined container classes.

[2] Note how assignment through a sequence_buffer is implemented. In general, unary operator* must be defined so that it returns a proxy object, where the proxy object defines operator= to perform the output operation. In this case, for the sake of simplicity, the proxy object is the sequence_buffer itself. That is, *i simply returns i , and *i = t is equivalent to i = t . You should not, however, rely on this behavior. It is an implementation detail, and it is not guaranteed to remain the same in future versions.

Output Iterator, rope , front_insert_iterator , back_insert_iterator , insert_iterator

Category: algorithms

Component type: function

template

UnaryFunction for_each(InputIterator first, InputIterator last, UnaryFunction f);

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]