multiset::operator= in C++ STL

Difficulty Level : Basic
Last Updated : 16 Mar, 2018

Multisets are a type of associative containers similar to set, with an exception that multiple elements can have same values.

multiset::operator=

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 :

multisetname1 = (multisetname2)
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.

set::operator=

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 :

setname1 = (setname2)
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.

Examples:

Input  :  mymultiset1 = 1, 2, 3
          mymultiset2 = 3, 2, 1, 4
          mymultiset1 = mymultiset2;
Output :  mymultiset1 = 3, 2, 1, 4

Input  :  mymultiset1 = 2, 6, 1, 5
          mymultiset2 = 3, 2
          mymultiset1 = mymultiset2;
Output :  mymultiset1 = 3, 2

Input  :  myset1 = 1, 2, 3
          myset2 = 3, 2, 1, 4
          myset1 = myset2;
Output :  myset1 = 3, 2, 1, 4

Input  :  myset1 = 2, 6, 1, 5
          myset2 = 3, 2
          myset1 = myset2;
Output :  myset1 = 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.

// INTEGER MULISET EXAMPLE 
// CPP program to illustrate 
// Implementation of = operator 
#include <iostream> 
#include <set> 
using namespace std; 
   
int main() 
{ 
    multiset<int> mymultiset1{ 1, 7, 4, 9, 0}; 
    multiset<int> mymultiset2{ 3, 4 }; 
    mymultiset1 = mymultiset2; 
    cout << "mymultiset1 = "; 
    for (auto it = mymultiset1.begin(); 
              it != mymultiset1.end(); ++it) 
        cout << ' ' << *it; 
    return 0; 
} 

Output:

mymultilist1 = 3 4

// CHARACTER MULTISET EXAMPLE 
// CPP program to illustrate 
// Implementation of = operator 
#include <iostream> 
#include <set> 
using namespace std; 
   
int main() 
{ 
    multiset<char> mymultiset1{ 'a', 'b', 'c'}; 
    multiset<char> mymultiset2{ 'x', 'y' }; 
    mymultiset1 = mymultiset2; 
    cout << "mymultiset1 = "; 
    for (auto it = mymultiset1.begin(); 
              it != mymultiset1.end(); ++it) 
        cout << ' ' << *it; 
    return 0; 
} 

Output:

mymultilist1 = x y

// STRING MULTISET EXAMPLE 
// CPP program to illustrate 
// Implementation of = operator 
#include <iostream> 
#include <set> 
#include<string> 
using namespace std; 
   
int main() 
{ 
    multiset<string> mymultiset1{ "This","is","a","computer science portal"}; 
    multiset<string> mymultiset2{ "GeeksForGeeks" }; 
    mymultiset1 = mymultiset2; 
    cout << "mymultiset1 = "; 
    for (auto it = mymultiset1.begin(); 
              it != mymultiset1.end(); ++it) 
        cout << ' ' << *it; 
    return 0; 
} 

Output:

mymultilist1 = GeeksForGeeks

Time Complexity: O(n)

// CPP program to illustrate 
// Implementation of = operator 
#include <iostream> 
#include <set> 
#include<string> 
using namespace std; 
   
int main() 
{ 
    set<string> myset1{ "This","is","a","computer science portal"}; 
    set<string> myset2{ "GeeksForGeeks" }; 
    myset1 = myset2; 
    cout << "myset1 = "; 
    for (auto it = myset1.begin(); 
              it != myset1.end(); ++it) 
        cout << ' ' << *it; 
    return 0; 
} 

Output:

mylist1 = GeeksForGeeks

Time Complexity: O(n)

Attention reader! Don’t stop learning now. Get hold of all the important C++ Foundation and STL concepts with the C++ Foundation and STL courses at a student-friendly price and become industry ready.

My Personal Notes

Related Articles