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multimap::cbegin() and multimap::cend() in C++ STL

  1. multimap::cbegin() is a built-in function in C++ STL which returns a constant iterator referring to the first element in the multimap container. Since multimap container contains the element in an ordered way, cbegin() will point to that element that will come first according to the container’s sorting criterion.

    Syntax:

    multimap_name.cbegin()
    

    Parameters: The function does not accept any parameter.

    Return Value: The function returns a constant iterator referring to the first element in the multimap container.

    // C++ program to illustrate
    // the multimap::cbegin() function
    #include <bits/stdc++.h>
    using namespace std;
      
    int main()
    {
      
        // initialize container
        multimap<int, int> mp;
      
        // insert elements in random order
        mp.insert({ 2, 30 });
        mp.insert({ 1, 40 });
        mp.insert({ 3, 60 });
        mp.insert({ 4, 20 });
        mp.insert({ 5, 50 });
      
        auto ite = mp.cbegin();
      
        cout << "The first element is: ";
        cout << "{" << ite->first << ", "
             << ite->second << "} ";
      
        // prints the elements
        cout << " The multimap is : ";
        cout << "KEY ELEMENT ";
        for (auto itr = mp.cbegin(); itr != mp.cend(); ++itr) {
            cout << itr->first
                 << ' ' << itr->second << ' ';
        }
        return 0;
    }

    Output:

    The first element is: {1, 40}
    
    The multimap is : 
    KEY    ELEMENT
    1    40
    2    30
    3    60
    4    20
    5    50
    
  2. multimap::cend() is a builtin function in C++ STL which returns a constant iterator pointing to the theoretical element that follows last element in the multimap. Since multimap container contains the element in an ordered way, cend() will point to that follows the last element according to the container’s sorting criterion.

    Syntax:



    multimap_name.cend()
    

    Parameters: The function does not accept any parameter.

    Return Value: The function returns a constant iterator pointing to the theoretical element that follows the last element in the multimap.

    // C++ program to illustrate
    // the multimap::cend() function
    #include <bits/stdc++.h>
    using namespace std;
      
    int main()
    {
      
        // initialize container
        multimap<int, int> mp;
      
        // insert elements in random order
        mp.insert({ 2, 30 });
        mp.insert({ 1, 40 });
        mp.insert({ 3, 60 });
        mp.insert({ 4, 20 });
        mp.insert({ 5, 50 });
      
        // print the elements
        cout << " The multimap is : ";
        cout << "KEY ELEMENT ";
        for (auto itr = mp.cbegin(); itr != mp.cend(); ++itr) {
            cout << itr->first
                 << ' ' << itr->second << ' ';
        }
        return 0;
    }

    Output:

    The multimap is : 
    KEY    ELEMENT
    1    40
    2    30
    3    60
    4    20
    5    50
    


This article is attributed to GeeksforGeeks.org

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