replace_copy_if

 Category: algorithms Component type: function

Prototype

```template <class InputIterator, class OutputIterator, class Predicate, class T>
OutputIterator replace_copy_if(InputIterator first, InputIterator last,
OutputIterator result, Predicate pred,
const T& new_value)
```

Description

`Replace_copy_if` copies elements from the range `[first, last)` to the range `[result, result + (last-first))`, except that any element for which `pred` is `true` is not copied; `new_value` is copied instead. More precisely, for every integer `n` such that `0 <= n < last-first`, `replace_copy_if` performs the assignment `*(result+n) = new_value` if `pred(*(first+n))`, and `*(result+n) = *(first+n)` otherwise.

Definition

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

Requirements on types

• `InputIterator` is a model of InputIterator.
• `OutputIterator` is a model of OutputIterator.
• `Predicate` is a model of Predicate.
• `T` is convertible to `Predicate`'s argument type.
• `T` is Assignable.
• `T` is convertible to a type in `OutputIterator`'s set of value types.

Preconditions

• `[first, last)` is a valid range.
• There is enough space in the output range to store the copied values. That is, `[result, result + (last-first))` is a valid range.
• `result` is not an iterator within the range `[first, last)`.

Complexity

Linear. `Replace_copy` performs exactly `last - first` applications of `pred` and exactly `last - first` assignments.

Example

Copy elements from one Vector to another, replacing all negative numbers with `0`.

```Vector<int> V1;
V1.push_back(1);
V1.push_back(-1);
V1.push_back(-5);
V1.push_back(2);

Vector<int> V2(4);

replace_copy_if(V1.begin(), V1.end(), V2.begin(),
bind2nd(less<int>(), 0),
0);
assert(V[0] == 1 && V[1] == 0 && V[2] == 0 && V[3] == 2);
```

Notes

`copy`, `replace`, `replace_if`, `replace_copy`