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std::unordered_map max_size() method

// Const version only
size_type max_size() const noexcept;

Returns the maximum number of elements the container is able to hold due to system or library implementation limitations, i.e. std::distance(begin(), end()) for the largest container.

Parameters

(none)

Return value

Maximum number of elements.

Complexity

Constant.

Exceptions

(none)

Notes

This value typically reflects the theoretical limit on the size of the container, at most std::numeric_limits<difference_type>::max(). At runtime, the size of the container may be limited to a value smaller than max_size() by the amount of RAM available.

Example

Main.cpp
#include <iostream>
#include <locale>
#include <unordered_map>

int main()
{
std::unordered_map<char, char> q;
std::cout.imbue(std::locale("en_US.UTF-8"));
std::cout << "Maximum size of a std::unordered_map is " << q.max_size() << '\n';
}
Possible output
Maximum size of a std::unordered_map is 768,614,336,404,564,650
This article originates from this CppReference page. It was likely altered for improvements or editors' preference. Click "Edit this page" to see all changes made to this document.
Hover to see the original license.

std::unordered_map max_size() method

// Const version only
size_type max_size() const noexcept;

Returns the maximum number of elements the container is able to hold due to system or library implementation limitations, i.e. std::distance(begin(), end()) for the largest container.

Parameters

(none)

Return value

Maximum number of elements.

Complexity

Constant.

Exceptions

(none)

Notes

This value typically reflects the theoretical limit on the size of the container, at most std::numeric_limits<difference_type>::max(). At runtime, the size of the container may be limited to a value smaller than max_size() by the amount of RAM available.

Example

Main.cpp
#include <iostream>
#include <locale>
#include <unordered_map>

int main()
{
std::unordered_map<char, char> q;
std::cout.imbue(std::locale("en_US.UTF-8"));
std::cout << "Maximum size of a std::unordered_map is " << q.max_size() << '\n';
}
Possible output
Maximum size of a std::unordered_map is 768,614,336,404,564,650
This article originates from this CppReference page. It was likely altered for improvements or editors' preference. Click "Edit this page" to see all changes made to this document.
Hover to see the original license.