Skip to content
Related Articles

Related Articles

Improve Article

map cbegin() and cend() function in C++ STL

  • Difficulty Level : Basic
  • Last Updated : 29 Jun, 2018
  1. map::cbegin() is a built-in function in C++ STL which returns a constant iterator referring to the first element in the map container. Since map 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:

    map_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 map container.




    // C++ program to illustrate
    // the map::cbegin() function
    #include <bits/stdc++.h>
    using namespace std;
      
    int main()
    {
      
        // initialize container
        map<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 << "}\n";
      
        // prints the elements
        cout << "\nThe map is : \n";
        cout << "KEY\tELEMENT\n";
        for (auto itr = mp.cbegin(); itr != mp.cend(); ++itr) {
            cout << itr->first
                 << '\t' << itr->second << '\n';
        }
        return 0;
    }
    Output:
    The first element is: {1, 40}
    
    The map is : 
    KEY    ELEMENT
    1    40
    2    30
    3    60
    4    20
    5    50
    
  2. map::cend() is a built-in function in C++ STL which returns a constant iterator pointing to the theoretical element that follows last element in the multimap. Since map 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:



    map_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 map.




    // C++ program to illustrate
    // the map::cend() function
    #include <bits/stdc++.h>
    using namespace std;
      
    int main()
    {
      
        // initialize container
        map<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 << "\nThe map is : \n";
        cout << "KEY\tELEMENT\n";
        for (auto itr = mp.cbegin(); itr != mp.cend(); ++itr) {
            cout << itr->first
                 << '\t' << itr->second << '\n';
        }
        return 0;
    }
    Output:
    The map is : 
    KEY    ELEMENT
    1    40
    2    30
    3    60
    4    20
    5    50
    
Want to learn from the best curated videos and practice problems, check out the C++ Foundation Course for Basic to Advanced C++ and C++ STL Course for foundation plus STL.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.



My Personal Notes arrow_drop_up
Recommended Articles
Page :