C++ - List merge() Function

The C++ list::merge function is used to delete all occurrences of specified element from the list container.

Syntax

C++98
C++11

void merge (list& x);
 
template <class Compare>
  void merge (list& x, Compare comp);

void merge (list& x);
void merge (list&& x);

template <class Compare>
  void merge (list& x, Compare comp);
template <class Compare>
  void merge (list&& x, Compare comp);

Parameters

val Specify the value of the element which need to be merged from the list.

Return Value

None.

Time Complexity

Linear i.e, Θ(n).

Example:

In the below example, the list::merge function is used to delete all occurrences of specified element from the list called MyList.

#include <iostream>
#include <list>
using namespace std;
 
int main (){
  list<int> MyList{10, 20, 30, 40, 50, 30, 30, 40};
  list<int>::iterator it;

  cout<<"MyList contains: ";
  for(it = MyList.begin(); it != MyList.end(); it++)
    cout<<*it<<" ";

  //Remove all occurrences of 30 from the list
  cout<<"\n\nRemove all occurrences of 30 from the MyList.\n";
  MyList.merge(30);
  
  cout<<"Now, MyList contains: ";
  for(it = MyList.begin(); it != MyList.end(); it++)
    cout<<*it<<" ";

  return 0;
}

The output of the above code will be:

MyList contains: 10 20 30 40 50 30 30 40 

Remove all occurrences of 30 from the MyList.
Now, MyList contains: 10 20 40 50 40

❮ C++ - List