std::set<Key,Compare,Allocator>::max_size

 

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operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Deduction guides(C++17)

 

size_type max_size() const;		(until C++11)
size_type max_size() const noexcept;		(since C++11)

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.

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

Run this code

#include <iostream>
#include <set>
 
const char* separate(unsigned long long n)
{
    static char buf[64];
 
    int i{sizeof(buf) - 1}, j{};
    buf[i] = '\0';
 
    do {
        buf[--i] = '0' + (n % 10);
        if (j++ % 3 == 2)
            buf[--i] = '\'';
    } while (n /= 10);
 
    return buf + i + (buf[i] == '\'' ? 1 : 0);
}
 
int main()
{
    std::set<char> s;
    std::cout << "Maximum size of a 'set' is " << separate(s.max_size()) << "\n";
}

Possible output:

Maximum size of a 'set' is 576'460'752'303'423'487

See also

size	returns the number of elements (public member function)