unordered_multimap clear() function in C++ STL (original) (raw)

Last Updated : 8 Aug, 2018

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:

unorderedmultimapname.clear()

Parameters: The function does not accept any parameter. Return Value: It returns nothing. Below programs illustrates the above function: Program 1:

CPP `

// 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:

Key and Elements of multimap are: {15, 150} {30, 300} {20, 200} {10, 100} {10, 100} Size of container after function call: 0

Program 2:

CPP `

// 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