list::operator= in C++ STL

Lists are containers used in C++ to store data in a non contiguous fashion, Normally, Arrays and Vectors are contiguous in nature, therefore the insertion and deletion operations are costlier as compared to the insertion and deletion option in Lists.


This operator is used to assign new contents to the container by replacing the existing contents.
It also modifies the size according to the new contents.

Syntax :

listname1 = (listname2)
Parameters :
Another container of the same type.
Result :
Assign the contents of the container passed as 
parameter to the container written on left side of the operator.


Input  :  mylist1 = 1, 2, 3
          mylist2 = 3, 2, 1, 4
          mylist1 = mylist2;
Output :  mylist1 = 3, 2, 1, 4

Input  :  mylist1 = 2, 6, 1, 5
          mylist2 = 3, 2
          mylist1 = mylist2;
Output :  mylist1 = 3, 2

Errors and Exceptions

1. If the containers are of different types, an error is thrown.
2. It has a basic no exception throw guarantee otherwise.





// CPP program to illustrate
// Implementation of = operator
#include <iostream>
#include <list>
using namespace std;
int main()
    list<int> mylist1{ 1, 2, 3 };
    list<int> mylist2{ 3, 2, 1, 4 };
    mylist1 = mylist2;
    cout << "mylist1 = ";
    for (auto it = mylist1.begin();
              it != mylist1.end(); ++it)
        cout << ' ' << *it;
    return 0;



mylist1 = 3 2 1 4

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