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# Remove all consecutive duplicate elements from the list | C++ STL

Example of list.unique() function in C++ STL: Here, we are going to learn how to remove consecutive duplicate elements from the list?
Submitted by IncludeHelp, on October 31, 2018

## Problem statement

Given a list with some of the elements and we have to remove consecutive duplicate elements from the list in C++ STL.

## list.unique() function

In C++ STL, to remove consecutive duplicate elements, we use a library function of "list" header, that is unique(), this function removes all consecutive duplicate elements from the list (similar to other containers also). And we get the list without consecutive duplicate elements.

Here is an example with sample input and output:

```Input:
List = {10, 10, 20, 30, 30, 10, 20, 40, 40, 50}

Output:
List elements are
10 10 20 30 30 10 20 40 40 50
List after removing consecutive duplicate elements
10 20 30 10 20 40 50
```

## C++ program to remove all consecutive duplicate elements from the list

```#include <iostream>
#include <list>
using namespace std;

// function to display the list
void dispList(list<int> L) {
// declaring iterator to the list
list<int>::iterator l_iter;
for (l_iter = L.begin(); l_iter != L.end(); l_iter++) cout << *l_iter << " ";
cout << endl;
}

int main() {
// declaring a list
list<int> iList = {10, 10, 20, 30, 30, 10, 20, 40, 40, 50};

// printing list elements
cout << "List elements are" << endl;
dispList(iList);

// remove all consecutive duplicate elements
iList.unique();
cout << "List after removing consecutive duplicate elements" << endl;
dispList(iList);

return 0;
}
```

### Output

```List elements are
10 10 20 30 30 10 20 40 40 50
List after removing consecutive duplicate elements
10 20 30 10 20 40 50
```