# multimap clear() function in C++ STL

In this article, we will be discussing the working, syntax, and examples of multimap::clear() function in C++ STL.

## What is Multimap in C++ STL?

Multimaps are the associative containers, which are similar to map containers. It also facilitates to store the elements formed by a combination of key-value and mapped value in a specific order. In a multimap container there can be multiple elements associated with the same key. The data is internally always sorted with the help of its associated keys.

## What is multimap::clear()?

multimap::clear() function is an inbuilt function in C++ STL, which is defined in <map> header file. clear() is used to remove all the content from the associated multimap container. This function removes all the values and makes the size of the container 0.

## Syntax

Map_name.clear();

## Parameter

This function accepts no parameter.

## Return value

This function returns nothing

Input

multimap<char, int > newmap;
newmap.insert(make_pair(‘a’, 1));
newmap.insert(make_pair(‘b’, 2));
newmap.insert(make_pair(‘c’, 3));
newmap.clear();

Output

size of the multimap is: 0

## Example

Live Demo

#include<iostream>
#include<map&g;
using namespace std;
int main(){
multimap<int,int > mul_1;
//inserting elements to multimap1
mul_1.insert({1,10});
mul_1.insert({2,20});
mul_1.insert({3,30});
mul_1.insert({4,40});
mul_1.insert({5,50});
cout << "Multimap size before using clear function : ";
cout <<mul_1.size() << '\n';
mul_1.clear();
cout << "Multimap size after using clear function : ";
cout << mul_1.size() << '\n';
}

## Output

If we run the above code it will generate the following output −

Multimap size before using clear function : 5
Multimap size after using clear function : 0