C++ In a Nutshell

Name

remove_if function template — Reorders a range to remove elements for which a predicate returns false

Synopsis

template<typename FwdIter, typename Predicate>
  FwdIter remove_if(FwdIter first, FwdIter last, Predicate pred);

The remove_if function template “removes” items for which pred returns false from the range [first, last). The return value is one past the new end of the range. The relative order of items that are not removed is stable.

Nothing is actually erased from the underlying container; instead, items to the right are assigned to new positions so they overwrite the elements for which pred returns false. See Figure 13-13 (under remove_copy) for an example of the removal process.

Technical Notes

The remove_if function template assigns *(first + n++) = *(first + m), in which n starts at 0, for all values of m in [0, last - first), in which pred(*(first + m)) is false. The return value is first + n.

Complexity is linear: exactly last - first comparisons are performed.

See Also

remove function template, remove_copy_if function template, replace_if function template