C++ Array::max_size() Function

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The C++ std::array::max_size() function is used to return the maximum number of elements that the array can hold. This value is constant and determined at compile time, as array has a fixed size. It is equal to the size specified when the array is created.

Syntax

Following is the syntax for std::array::max_size() function.

constexpr size_type max_size() noexcept;

Parameters

It does not accepts any parameter.

Return Value

This function returns the maximum number of elements that the array can hold.

Exceptions

This function never throws exception.

Time complexity

Constant i.e. O(1)

Example 1

In the following example, we are going to consider the basic usage of the max_size() function.

#include <iostream>
#include <array>
int main() {
   std::array < int, 5 > a = {11,23,34};
   std::cout << "Result : " << a.max_size() << std::endl;
   return 0;
}

Output

Following is the output of the above code −

Result : 5

Example 2

Consider the following example, where we are going to use the max_size() with different data types.

#include <iostream>
#include <array>
int main() {
   std::array < char, 6 > a;
   std::array < float, 11 > b;
   std::cout << "Result of char array: " << a.max_size() << std::endl;
   std::cout << "Result of float array: " << b.max_size() << std::endl;
   return 0;
}

Output

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

Result of char array: 6
Result of float array: 11

Example 3

Let's look at the following example, where we are going to use the size() along with the max_size() function.

#include <iostream>
#include <array>
using namespace std;
int main(void) {
   array < int, 10 > arr;
   cout << "maximum size of arr = " << arr.max_size() <<
      endl;
   cout << "size of arr  = " << arr.size() <<
      endl;
   return 0;
}

Output

Output of the above code is as follows −

maximum size of arr = 10
size of arr  = 10