Map Max Size in C++ STL

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

What is a Map in C++ STL?

Maps are the associative container, which facilitates to store the elements formed by a combination of key value and mapped value in a specific order. In a map container the data is internally always sorted with the help of its associated keys. The values in the map container are accessed by its unique keys.

What is a map::max_size()?

map::max_size() function is an inbuilt function in C++ STL, which is defined in <map> header file. max_size() is used to return the maximum size of the map container.

This function is used to check the maximum number of values that a map container can hold. The size is like the potential of the container, hence there is no guarantee that it can reach that value or not.

Syntax

Map_name.max_size();

Parameter

This function accepts no parameter.

Return value

This function returns the number of elements a container can hold.

Input 

map<char, int> newmap;
newmap.max_size();

Output 

Max size of map is: 461168601842738790

Example

 Live Demo

#include <bits/stdc++.h>
using namespace std;
int main(){
   map<int, int> TP_1, TP_2;
   TP_1.insert({ 0, 10 });
   cout<<"Max size of map with elements is: " << TP_1.max_size();
   cout<<"\Max size of map without elements is: " << TP_2.max_size();
   return 0;
}

Output

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

Max size of map with elements is: 461168601842738790
Max size of map without elements is: 461168601842738790