As is commonly understood, the C++ programming language offers a variety of built-in functions that assist in reducing the need for extensive code writing. An example of such a function is the find function within the multimap, which is part of the extensive library provided by the C++ Standard Template Library (STL). This function enables the retrieval of an iterator that points to the location of the key within the multimap, facilitating efficient data traversal within both large and small multimap structures. Notably, the performance of the multimap's find operation surpasses that of the emplace operation. When utilizing multimap emplace find, key elements are inserted with a hint, ensuring that the insertion position remains unaffected.
Multimap in C++ Code
Example
// Here we are writing down the C++ programming language code to
// demonstrate
// the concept of multimap find() in C++ STL(Standard Template Library)
#include <iostream>
#include <iterator>
#include <map>
using namespace std;
// The main driver code functionality starts from here!
int main()
{
// Here, we are trying to create an initializer container
// which will help us with creating a multimap using C++ STL
multimap<int, int> gquiz1;
// these insert functions which we have written below help us
// with creating a multimap holding the values inserted below!
gquiz1.insert(pair<int, int>(1, 40));
gquiz1.insert(pair<int, int>(2, 30));
gquiz1.insert(pair<int, int>(3, 60));
gquiz1.insert(pair<int, int>(6, 50));
gquiz1.insert(pair<int, int>(6, 10));
// elements that we are going to display on the Output screen are
multimap<int, int>::iterator itr;
cout << "\nThe multimap gquiz1 is : \n";
cout << "\tKEY\tELEMENT\n";
// here we are writing the for loop, which contains the auto code
// functionality containing the find() function at different positions
for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
cout << endl;
// here, we are trying to add elements randomly,
// as it helps us to check the sorted keys property in C++ STL
gquiz1.insert(pair<int, int>(4, 50));
gquiz1.insert(pair<int, int>(5, 10));
// the below code helps us with printing multimap gquiz1 again
cout << "\nmultimap quiz1 after"
<< " adding the extra elements is: \n";
cout << "\tkey\telement\n";
for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
cout << endl;
// the below code snippet below assigning the elements from quiz1 to quiz2
multimap<int, int> gquiz2(gquiz1.begin(),
gquiz1.end());
// the below code snippet prints all the elements of the multimap gquiz2
cout << "\nThe multimap gquiz2 after"
<< " assign from gquiz1 is : \n";
cout << "\tKEY\tELEMENT\n";
for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
cout << endl;
return 0;
}
Output:
Output
The multimap gquiz1 is :
KEY ELEMENT
1 40
2 30
3 60
6 50
6 10
Multimap quiz1 after adding the extra elements is :
key element
1 40
2 30
3 60
4 50
5 10
6 50
6 10
The multimap gquiz2 after assign from gquiz1 is :
KEY ELEMENT
1 40
2 30
3 60
4 50
5 10
6 50
6 10
multimap::emplace_hint Function in C++ STL
Syntax
Example
multimap_name.emplace_hint(position, key, element)
C++ Code
Example
// Here we are writing down the C++ programming language code to
// demonstrate
// the concept of multimap::emplace_hint() function in the
// C++ STL(Standard Template Library)
#include <bits/stdc++.h>
using namespace std;
// the main driver code functionality starts from here
int main()
{
// Here, we are trying to create an initializer container
// which will help us with creating a multimap using C++ STL
multimap<int, int> mp;
// these emplace functions which we have written below help us
// with creating a multimap holding the values inserted below!
mp.emplace_hint(mp.begin(), 12, 230); // this is faster
mp.emplace_hint(mp.begin(), 14, 440); // this is faster
mp.emplace_hint(mp.begin(), 42, 960); // this is slower
mp.emplace_hint(mp.begin(), 32, 620); // this is slower
mp.emplace_hint(mp.begin(), 31, 540); // this is faster
mp.emplace_hint(mp.begin(), 17, 150); // this is faster
// elements that we are going to display on the Output screen are
cout << "\nThe multimap is : \n";
cout << "KEY\tELEMENT\n";
// here we are writing the for loop, which contains the auto code
// functionality containing the find() function at different positions
for (auto itr = mp.begin(); itr != mp.end(); itr++)
cout << itr->first << "\t" << itr->second << endl;
return 0;
// The main driver code functionality ends from here!
}
Output:
Output
The multimap is :
KEY ELEMENT
12 230
14 440
17 150
31 540
32 620
42 960
