map value_comp() in C++ STL

The std::map::value_comp() is a function in C++ STL. It returns a function object that compares objects of type std::map::value.

Syntax:

value_compare value_comp() const

Parameters: It does not accept any parameters.

Returns: This method returns a function object that compares objects of type std::map::value.

Time Complexity: O(1)



Below examples illustrate the map::value_comp() method:

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ program to illustrate
// map::value_comp() method
  
#include <iostream>
#include <map>
using namespace std;
  
int main()
{
    map<char, int> m = {
        { 'a', 1 },
        { 'b', 2 },
        { 'c', 3 },
        { 'd', 4 },
        { 'e', 5 },
    };
  
    auto last = *m.rbegin();
    auto i = m.begin();
  
    cout << "Map contains "
         << "following elements"
         << endl;
  
    do {
  
        cout << i->first
             << " = "
             << i->second
             << endl;
    } while (m.value_comp()(*i++, last));
  
    return 0;
}
chevron_right

Output:
Map contains following elements
a = 1
b = 2
c = 3
d = 4
e = 5

Example 2:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ Program to illustrate
// map::rbegin() method
  
#include <iostream>
#include <map>
using namespace std;
  
int main()
{
  
    map<char, char> m = {
        { 'a', 'A' },
        { 'b', 'B' },
        { 'c', 'C' },
        { 'd', 'D' },
        { 'e', 'E' },
    };
  
    auto last = *m.rbegin();
    auto i = m.begin();
  
    cout << "Map contains "
         << "following elements"
         << endl;
  
    do {
  
        cout << i->first
             << " = "
             << i->second
             << endl;
    } while (m.value_comp()(*i++, last));
  
    return 0;
}
chevron_right

Output:
Map contains following elements
a = A
b = B
c = C
d = D
e = E

Rated as one of the most sought after skills in the industry, own the basics of coding with our C++ STL Course and master the very concepts by intense problem-solving.





Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.


Article Tags :
C++
Practice Tags :