unordered_multimap emplace() function in C++ STL
The unordered_multimap::emplace() is a built-in function in C++ STL which inserts a new {key, element} in the unordered_multimap container. The insertion is done automatically at the position according to the container’s criterion. It increases the size of the container by one.
Syntax:
unordered_multimap_name.emplace(key, element)
Parameters: The function accepts a single mandatory parameter key and element which is to be inserted in the container.
Return Value: It returns an iterator which points to the newly inserted element.
Below programs illustrates the above function:
Program 1:
#include <iostream>
#include <string>
#include <unordered_map>
using namespace std;
int main()
{
unordered_multimap< int , int > sample;
sample.emplace(1, 2);
sample.emplace(1, 2);
sample.emplace(1, 3);
sample.emplace(4, 9);
sample.emplace(60, 89);
cout << "Key and Elements: \n" ;
for ( auto it = sample.begin(); it != sample.end(); it++)
cout << "{" << it->first << ":" << it->second << "}\n " ;
return 0;
}
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Output:
Key and Elements:
{60:89}
{4:9}
{1:3}
{1:2}
{1:2}
Program 2:
#include <iostream>
#include <string>
#include <unordered_map>
using namespace std;
int main()
{
unordered_multimap<string, string> sample;
sample.emplace( "gopal" , "dave" );
sample.emplace( "gopal" , "dave" );
sample.emplace( "Geeks" , "C++" );
sample.emplace( "multimap" , "functions" );
sample.emplace( "multimap" , "functions" );
cout << "Key and Elements: \n" ;
for ( auto it = sample.begin(); it != sample.end(); it++)
cout << "{" << it->first << ":" << it->second << "}\n " ;
return 0;
}
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Output:
Key and Elements:
{multimap:functions}
{multimap:functions}
{Geeks:C++}
{gopal:dave}
{gopal:dave}
Last Updated :
08 Aug, 2018
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