# C++ Vector Library - vector() Function

#### Complete Python Prime Pack for 2023

9 Courses     2 eBooks

#### Artificial Intelligence & Machine Learning Prime Pack

6 Courses     1 eBooks

#### Java Prime Pack 2023

8 Courses     2 eBooks

## Description

The C++ range constructor std::vector::vector() constructs a container with as many elements in range of first to last.

Assigns value to container elements in range of [first, last].

## Declaration

Following is the declaration for range constructor std::vector::vector() form std::vector header.

### C++98

```template <class InputIterator> vector (InputIterator first, InputIterator last,
const allocator_type& alloc = allocator_type());
```

### C++11

```template <class InputIterator> vector (InputIterator first, InputIterator last,
const allocator_type& alloc = allocator_type());
```

## Parameters

• first − Input iterator to the initial position in range.

• last − Input itertor to the final position in range.

## Return value

Constructor never returns value.

## Exceptions

This member function never throws exception.

Linear i.e. O(n)

## Example

The following example shows the usage of range constructor std::vector::vector().

```#include <iostream>
#include <vector>

using namespace std;

int main(void) {
vector<int> v1(5);

/* assigned value to vector v1 */
for (int i = 0; i < v1.size(); ++i)
v1[i] = i + 1;

/* create a range constructor v2 from v1 */
vector<int> v2(v1.begin(), v1.end());

for (int i = 0; i < v2.size(); ++i)
cout << v2[i] << endl;

return 0;
}
```

Let us compile and run the above program, this will produce the following result −

```1
2
3
4
5
```
vector.htm