C++ Multiset emplace_hint()

C++ Multiset emplace_hint() function is used to extend the multiset container by inserting new elements into the container using hint as a position for element. Elements are built directly (neither copied nor moved).

The constructor of the element is called by giving the arguments args passed to this function.

Syntax

  template <class… Args>      iterator emplace_hint (const_iterator position, Args&&… args);  //since C++ 11  

Parameter

args: The arguments forwarded to construct an element to be inserted into the container.

position: Hint for the position to insert the new elements.

Return value

emplace_hint() function returns an iterator to the newly inserted elements. If element is already exists, insertion is failed and returns iterator to the existing element.

Complexity

If position is not specified then complexity will be logarithmic in container size.

If position is given then complexity will be amortized constant.

Iterator validity

No changes.

Data Races

The container is modified.

Iterating ranges in the container is not safe although concurrently accessing exiting elements is safe.

Exception Safety

If an exception is thrown, there are no changes in the container.

Example 1

Let’s see the simple example to insert the elements into the multiset:

  #include <iostream>  #include <set>    using namespace std;    int main(void) {     multiset<int> m = {30, 20, 30, 10};                   m.emplace_hint(m.end(), 40);     m.emplace_hint(m.begin(), 20);       cout << “Multiset contains following elements” << endl;       for (auto it = m.begin(); it != m.end(); ++it)        cout << *it<< endl;       return 0;  }  

Output:

Multiset contains following elements  10  20  20  30  30  40

In the above example, it simply inserts the element into the multiset m with the given value in the given positions.

Example 2

Let’s see a simple example:

  #include <set>    #include <string>    #include <iostream>        using namespace std;        template <typename M> void print(const M& m) {        cout << m.size() << ” elements: ” << endl;            for (const auto& p : m) {            cout << p << ”  ” ;        }            cout << endl;    }        int main()    {        multiset<string> m1;            // Emplace some test data        m1.emplace(“Ram”);        m1.emplace(“Deep”);        m1.emplace(“Sunil”);            cout << “multiset starting data: “;        print(m1);        cout << endl;            // Emplace with hint        // m1.end() should be the “next” element after this emplacement        m1.emplace_hint(m1.end(), “Deep”);            cout << “multiset modified, now contains “;        print(m1);        cout << endl;      return 0;    }  

Output:

multiset starting data: 3 elements:   Deep  Ram  Sunil      multiset modified, now contains 4 elements:   Deep  Deep  Ram  Sunil

Example 3

Let’s see a simple example to insert the elements into the multiset with the given position:

  #include <iostream>  #include <set>    using namespace std;    int main ()  {    multiset<char> mymultiset;    auto it = mymultiset.end();      it = mymultiset.emplace_hint(it,’b’);    mymultiset.emplace_hint(it,’a’);    mymultiset.emplace_hint(mymultiset.end(),’b’);      cout << “mymultiset contains:”;    for (auto& x: mymultiset)      cout << ” [” << x << ‘]’;      cout << ‘n’;      return 0;  }  

Output:

mymultiset contains: [a] [b] [b]

Example 4

Let’s see a simple example to insert the element:

  #include <iostream>  #include <set>  #include <string>    using namespace std;    int main() {      typedef multiset<string> city;       string name;     city fmly ;     int n;       cout<<“Enter the number of family members :”;     cin>>n;       cout<<“Enter the name of each member: n”;     for(int i =0; i<n; i++)     {         cin>> name;      // Get key           fmly.emplace_hint(fmly.begin(),name);              }             cout<<“nTotal members of family is:”<< fmly.size();          cout<<“nDetails of family members: n”;        cout<<“nName n ________________________n”;        city::iterator p;        for(p = fmly.begin(); p!=fmly.end(); p++)        {            cout<<(*p) <<” n “;        }           return 0;  }  

Output:

Enter the number of fmly members : 4  Enter the name of each member:   Deep  Sonu  Ajeet  Bob    Total memnber of fmly is:4  Details of fmly members:     Name    ________________________   Ajeet    Bob    Deep    Sonu

In the above example, it simply inserts the elements by the user’s choice in the beginning of multiset.

Next TopicC++ multiset

~multiset destructor begin()beginners c end()multiset multiset constructor operator professionals rbegin()rend()tutorial

C++ multiset emplace_hint() function

C++ Multiset emplace_hint()

Syntax

Parameter

Return value

Complexity

Iterator validity

Data Races

Exception Safety

Example 1

Example 2

Example 3

Example 4

Underwriting of Shares

C++ Math abs() Functions

You may also like