How to Find the Size of a Map in C++?
In C++ STL, maps are associative containers that store elements in a mapped fashion. Each element has a key value and a mapped value. No two mapped values can have the same key values. In this article, we will learn how to find the size of a map in C++ STL.
Example:
Input: myMap = { {1, "Sravan"}, {2, "Bobby"}, {3, "Srijay"}, {4, "Riya"} } Output: Size of map: 4
Find the Size of a Map in C++
In C++, you can find the size of a map using the std::map::size()
member function of the std::map
container. This function returns the number of key-value pairs stored in the map.
C++ Program to Find the Size of a Map
C++
// C++ program to find the size of the map #include <iostream> #include <map> using namespace std; int main() { // Create map - students_data map< int , string> students_data; // Insert 10 values into the above map students_data.insert(make_pair(1, "Sravan" )); students_data.insert(make_pair(2, "Bobby" )); students_data.insert(make_pair(3, "Siva Nagulu" )); students_data.insert(make_pair(4, "Bhavanarayana" )); students_data.insert(make_pair(5, "Ojaswi" )); students_data.insert(make_pair(6, "Gnanesh" )); students_data.insert(make_pair(7, "Sireesha" )); students_data.insert(make_pair(8, "Priyank Chowdhary" )); students_data.insert(make_pair(9, "Rohith" )); students_data.insert(make_pair(10, "Ravi Kumar" )); // Display the map size using the map::size() function. cout << "Total Students: " << students_data.size(); cout << endl; return 0; } |
Output
Total Students: 10
Time Complexity: O(1)
Space Complexity: O(1)
Time complexity: O(n)
Auxiliary Space: O(n)
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