C++ max_size()

The .max_size() member function returns the maximum number of elements an unordered_set can theoretically hold. This limit depends on the system and the implementation of the standard library, not on actual available memory.

Syntax

unordered_set_name.max_size()

Parameters:

This function takes no parameters.

Return value:

The method returns a value of type size_type, representing the theoretical maximum number of elements.

Example 1: Basic Usage

In this example, the program prints the maximum number of elements an unordered_set can theoretically hold:

#include <iostream>
#include <unordered_set>

int main() {
  std::unordered_set<int> numbers;

  std::cout << "Maximum size: " << numbers.max_size() << std::endl;

  return 0;
}

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The output will be:

Maximum size: 1152921504606846975

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Note: The actual value may vary depending on the system and implementation.

Example 2: Using Different Data Types

In this example, the max_size() value is shown for unordered_set containers holding different data types:

#include <iostream>
#include <unordered_set>

int main() {
  std::unordered_set<int> int_set;
  std::unordered_set<double> double_set;
  std::unordered_set<char> char_set;

  std::cout << "int max size: " << int_set.max_size() << std::endl;
  std::cout << "double max size: " << double_set.max_size() << std::endl;
  std::cout << "char max size: " << char_set.max_size() << std::endl;

  return 0;
}

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The output will be:

int max size: 1152921504606846975
double max size: 1152921504606846975
char max size: 1152921504606846975

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Codebyte Example

In this example, the program compares the current size of an unordered_set with its theoretical maximum:

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