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

Last Updated : 21 Aug, 2018

The unordered_multimap::size() is a built-in function in C++ STL which returns the size of the unordered_multimap. It denotes the number of elements in that container. Syntax:

unorderedmultimapname.size()

Parameters: The function does not accept any parameters. Return Value: It returns an integral values which denotes the size of the containers. Below programs illustrates the above function: Program 1:

CPP `

// C++ program to illustrate the // unordered_multimap::size() #include <bits/stdc++.h> using namespace std;

int main() {

// declaration
unordered_multimap<int, int> sample1, sample2;

// inserts key and element
// in sample1
sample1.insert({ 10, 100 });
sample1.insert({ 50, 500 });

// inserts key and element
// in sample1
sample2.insert({ 20, 200 });
sample2.insert({ 30, 300 });
sample2.insert({ 30, 150 });

cout << "The size of Sample1 is: " << sample1.size();

cout << "\nKey and Elements of Sample1 are:";
for (auto it = sample1.begin(); it != sample1.end(); it++) {
    cout << "{" << it->first << ", " << it->second << "} ";
}

cout << "\n\nThe size of Sample2 is: " << sample2.size();

cout << "\nKey and Elements of Sample2 are:";
for (auto it = sample2.begin(); it != sample2.end(); it++) {
    cout << "{" << it->first << ", " << it->second << "} ";
}

return 0;

}

`

Output:

The size of Sample1 is: 2 Key and Elements of Sample1 are:{50, 500} {10, 100}

The size of Sample2 is: 3 Key and Elements of Sample2 are:{20, 200} {30, 150} {30, 300}

Program 2:

CPP `

// C++ program to illustrate the // unordered_multimap::size() #include <bits/stdc++.h> using namespace std;

int main() {

// declaration
unordered_multimap<char, char> sample1, sample2;

// inserts key and element
// in sample1
sample1.insert({ 'a', 'A' });
sample1.insert({ 'g', 'G' });

// inserts key and element
// in sample1
sample2.insert({ 'b', 'B' });
sample2.insert({ 'c', 'C' });
sample2.insert({ 'd', 'D' });

cout << "The size of Sample1 is: " << sample1.size();

cout << "\nKey and Elements of Sample1 are:";
for (auto it = sample1.begin(); it != sample1.end(); it++) {
    cout << "{" << it->first << ", " << it->second << "} ";
}

cout << "\n\nThe size of Sample2 is: " << sample2.size();

cout << "\nKey and Elements of Sample2 are:";
for (auto it = sample2.begin(); it != sample2.end(); it++) {
    cout << "{" << it->first << ", " << it->second << "} ";
}

return 0;

}

`

Output:

The size of Sample1 is: 2 Key and Elements of Sample1 are:{g, G} {a, A}

The size of Sample2 is: 3 Key and Elements of Sample2 are:{d, D} {b, B} {c, C}