std::remove_copy, std::remove_copy_if

From Cppreference

Defined in header `<algorithm>`

template< class InputIterator, class OutputIterator, class T > OutputIterator remove_copy( InputIterator first, InputIterator last, OutputIterator d_first, const T& value );	(1)

template< class InputIterator, class OutputIterator, class UnaryPredicate > OutputIterator remove_copy_if( InputIterator first, InputIterator last, OutputIterator d_first, UnaryPredicate p );	(2)

Copies elements from the range [first, last), to another range beginning at d_first, omitting the elements which satisfy specific criteria. The first version ignores the elements that are equal to value, the second version ignores the elements for which predicate p returns true. Source and destination ranges cannot overlap.

template<class InputIterator, class OutputIterator, class T>
OutputIterator remove_copy(InputIterator first,
                           InputIterator last,
                           OutputIterator d_first,
                           const T& value)
{
    for (; first != last; ++first)
        if (!(*first == value)) {
            *d_first++ = *first;
        }
    }
    return d_first;
}

Second version

template<class InputIterator, class OutputIterator, class UnaryPredicate>
OutputIterator remove_copy_if(InputIterator first,
                              InputIterator last,
                              OutputIterator d_first,
                              UnaryPredicate p)
{
    for (; first != last; ++first)
        if (!p(*first)) {
            *d_first++ = *first;
        }
    }
    return d_first;
}

[edit] Example

The following code outputs a string while erasing the spaces on the fly.

#include <algorithm>
#include <iterator>
#include <string>
#include <iostream>
int main()
{
    std::string str = "Text with some   spaces";
    std::cout << "before: " << str << "\n";
 
    std::cout << "after:  ";
    std::remove_copy(str.begin(), str.end(),
                     std::ostream_iterator<char>(std::cout), ' ');
    std::cout << '\n';
}

Output:

before: Text with some   spaces
after:  Textwithsomespaces

[edit] See also

remove remove_if

removes elements satisfying specific criteria
(function template)

`first, last`	-	the range of elements to copy
`d_first`	-	the beginning of the destination range.
`value`	-	the value of the elements not to copy

std::remove_copy, std::remove_copy_if

From Cppreference

Contents

[edit] Parameters

[edit] Return value

[edit] Complexity

[edit] Equivalent function

[edit] Example

[edit] See also