The unordered_multimap::clear() is a built-in function in C++ STL which clears the contents of the unordered_multimap container. The final size of the container after the call of the function is 0.
Syntax:
CPP
CPP
unordered_multimap_name.clear()Parameters: The function does not accept any parameter. Return Value: It returns nothing. Below programs illustrates the above function: Program 1:
// C++ program to illustrate the
// unordered_multimap::clear()
#include <bits/stdc++.h>
using namespace std;
int main()
{
// declaration
unordered_multimap<int, int> sample;
// inserts key an delement
sample.insert({ 10, 100 });
sample.insert({ 10, 100 });
sample.insert({ 20, 200 });
sample.insert({ 30, 300 });
sample.insert({ 15, 150 });
cout << "Key and Elements of multimap are:";
for (auto it = sample.begin(); it != sample.end(); it++) {
cout << "\n{" << it->first << ", " << it->second << "}";
}
sample.clear();
cout << "\nSize of container after function call: "
<< sample.size();
return 0;
}
Output:
Program 2:
Key and Elements of multimap are:
{15, 150}
{30, 300}
{20, 200}
{10, 100}
{10, 100}
Size of container after function call: 0
// C++ program to illustrate the
// unordered_multimap::clear()
#include <bits/stdc++.h>
using namespace std;
int main()
{
// declaration
unordered_multimap<char, char> sample;
// inserts element
sample.insert({ 'a', 'b' });
sample.insert({ 'a', 'b' });
sample.insert({ 'b', 'c' });
sample.insert({ 'r', 'a' });
sample.insert({ 'c', 'b' });
cout << "Key and Elements of multimap are:";
for (auto it = sample.begin(); it != sample.end(); it++) {
cout << "\n{" << it->first << ", " << it->second << "}";
}
sample.clear();
cout << "\nSize of container after function call: "
<< sample.size();
return 0;
}
Output:
Key and Elements of multimap are:
{c, b}
{r, a}
{b, c}
{a, b}
{a, b}
Size of container after function call: 0
