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std::any::has_value(3)	       C++ Standard Libary	  std::any::has_value(3)

NAME
     std::any::has_value - std::any::has_value

Synopsis
	bool has_value() const noexcept;  (since C++17)

	Checks whether the object contains a value.

Parameters
	(none)

Return value
	true if instance contains a value, otherwise false.

Example
     // Run this code

      #include <any>
      #include <iostream>
      #include <string>

      int main()
      {
	  std::boolalpha(std::cout);

	  std::any a0;
	  std::cout << "a0.has_value(): " << a0.has_value() << '\n';

	  std::any a1 = 42;
	  std::cout << "a1.has_value(): " << a1.has_value() << '\n';
	  std::cout << "a1 = " << std::any_cast<int>(a1) << '\n';
	  a1.reset();
	  std::cout << "a1.has_value(): " << a1.has_value() << '\n';

	  auto a2 = std::make_any<std::string>("Milky Way");
	  std::cout << "a2.has_value(): " << a2.has_value() << '\n';
	  std::cout << "a2 = \"" << std::any_cast<std::string&>(a2) << "\"\n";
	  a2.reset();
	  std::cout << "a2.has_value(): " << a2.has_value() << '\n';
      }

Output:
      a0.has_value(): false
      a1.has_value(): true
      a1 = 42
      a1.has_value(): false
      a2.has_value(): true
      a2 = "Milky Way"
      a2.has_value(): false

See also
	reset destroys contained object
	      (public member function)

http://cppreference.com 	   2024.06.10		  std::any::has_value(3)
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