multimap find() in C++ STL

multimap::find() is a built-in function in C++ STL which returns an iterator or a constant iterator that refers to the position where the key is present in the multimap. In case of multiple same keys being present, the iterator that refers to one of the keys (typically the first one). In case we wish to get all the items with a given key, we may use equal_range(). If the key is not present in the multimap container, it returns an iterator or a constant iterator which refers to multimap.end(). 
Syntax: 

iterator multimap_name.find(key)
        or 
constant iterator multimap_name.find(key)

Parameters: The function accepts one mandatory parameter key which specifies the key to be searched in the multimap container. 
Return Value: The function returns an iterator or a constant iterator which refers to the position where the key is present in the multimap. If the key is not present in the multimap container, it returns an iterator or a constant iterator which refers to multimap.end(). 

CPP

// C++ program for illustration
// of multimap::find() 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({ 2, 60 });
    mp.insert({ 3, 20 });
    mp.insert({ 1, 50 });
    mp.insert({ 4, 50 });

    cout << "The elements from position 3 in multimap are : \n";
    cout << "KEY\tELEMENT\n";

    // find() function finds the position at which 3 is
    for (auto itr = mp.find(3); itr != mp.end(); itr++)
        cout << itr->first
             << '\t' << itr->second << '\n';

    return 0;
}

Output:

The elements from position 3 in multimap are : 
KEY    ELEMENT
3    20
4    50