std::deque erase() method

since C++11

// (1) Non const version only
iterator erase( const_iterator pos );

// (2) Non const version only
iterator erase( const_iterator first, const_iterator last );

until C++11

// (1) Non const version only
iterator erase( iterator pos );

// (2) Non const version only
iterator erase( iterator first, iterator last );

Erases the specified elements from the container.

• (1) Removes the element at pos.
• (2) Removes the elements in the range [ first, last ).

Invalidation

All iterators and references are invalidated, unless the erased elements are at the end or the beginning of the container, in which case only the iterators and references to the erased elements are invalidated.

since C++11

It is unspecified when the past-the-end iterator is invalidated.

until C++11

The past-the-end iterator is also invalidated unless the erased elements are at the beginning of the container and the last element is not erased.

important

The iterator pos must be valid and dereferenceable. Thus the end() iterator (which is valid, but is not dereferenceable) cannot be used as a value for pos.

note

For overload (2), the iterator first does not need to be dereferenceable if first == last - erasing an empty range is a no-op.

Parameters

• pos - iterator to the element to remove
• first, last - range of elements to remove

Type requirements

• T (the container's element type) must meet the requirements of MoveAssignable.

Return value

Iterator following the last removed element.

• For (1), if pos refers to the last element, then the end() iterator is returned.
• For (2), if last == end() prior to removal, then the updated end() iterator is returned.
• For (2), if [ first, last ) is an empty range, then last is returned.

Complexity

Linear: the number of calls to the destructor of T is the same as the number of elements erased, the number of calls to the assignment operator of T is no more than the lesser of the number of elements before the erased elements and the number of elements after the erased elements.

Exceptions

Does not throw, unless an exception is thrown by the assignment operator of T.

Example

Main.cpp

#include <deque>
#include <iostream>


void print_container(const std::deque<int>& c)
{
    for (int i : c)
        std::cout << i << " ";
    std::cout << '\n';
}

int main( )
{
    std::deque<int> c{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    print_container(c);

    c.erase(c.begin());
    print_container(c);

    c.erase(c.begin()+2, c.begin()+5);
    print_container(c);

    // Erase all even numbers
    for (std::deque<int>::iterator it = c.begin(); it != c.end();)
    {
        if (*it % 2 == 0)
            it = c.erase(it);
        else
            ++it;
    }
    print_container(c);
}

Possible output

0 1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 6 7 8 9
1 7 9