The **`nth_element()`
function** rearranges elements and works in such a way that the position of the $n^{th}$ element remains unchanged. The elements preceding the $n^{th}$ element must be less than elements succeeding it.

#    
## Syntax
```c++
nth_element(Begin, nth, End, Pred);
```

## Parameter
The `nth_element()` function accepts the following parameters:

* `Begin`: The iterator pointing to the first element in the range from first till $n^{th}$ element.

* `nth`: The iterator pointing to address from the range of first to last .
* `End`: The iterator pointing to the last element in the range from $n^{th}$ till last element.
* `Pred`: A user defined binary function which returns `true` if the two arguments passed are in order (*follows strict weak ordering*). 

## Return value
The function doesn’t return anything. 

# Code
Let’s have a look at the code.



#include <iostream>
#include <algorithm>
using namespace std;
bool comp(int x, int y)
{
  return (x < y);
}
int main()
{
  int arr[] = { 13, 21, 110, 15, 32, 65, 34, 47 };

  nth_element(arr, arr + 4, arr + 8, comp);
  for (int i = 0; i < 8; i++) 
    cout << arr[i] << " ";

  return 0;
}


## Explanation
* In lines 1 to 2, we imported the required libraries.

* In line 4, we defined a binary function to check whether the first argument is less than the second argument. (*We are going to use this function as a parameter to `nth_element()` function*).
* In line 8, we made a `main()` function.
* In line 10, we initialize an array.
* In line 12, we used the `nth_element()` function to fix the fourth element and it also rearranges the array in such a way that elements preceding the fourth element are less than the elements succeeding it.
* In line 13, we used a loop to access and display the elements of the array after using `nth_element()` function on array.

In this way, we can use the `nth_element()` function in C++.


What is the nth_element() function in C++?

Rearranges elements so the nth element is correctly positioned, with elements before it being lesser.