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:
// 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;} |
Output:
Map contains following elements a = 1 b = 2 c = 3 d = 4 e = 5
Example 2:
// 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;} |
Output:
Map contains following elements a = A b = B c = C d = D e = E
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