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      std::isunordered

      From cppreference.com
      <cpp‎ |numeric‎ |math
       
       
       
      Common mathematical functions
      Nearest integer floating point operations
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      (C++11)
      (C++11)
      (C++11)(C++11)(C++11)
      Floating point manipulation functions
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      (C++11)
      (C++11)
      Classification and comparison
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      (C++11)
      (C++11)
      (C++11)
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      isunordered
      (C++11)
      Types
      (C++11)
      (C++11)
      (C++11)
      Macro constants
       
      Defined in header<cmath>
      (1)
      bool isunordered(float x,float y);

      bool isunordered(double x,double y);

      bool isunordered(longdouble x,longdouble y);
      		(since C++11)
      (until C++23)
      constexprbool isunordered(/* floating-point-type */ x,
                                 /* floating-point-type */ y);
      		(since C++23)
      Defined in header<cmath>
      template<class Arithmetic1,class Arithmetic2>
      bool isunordered( Arithmetic1 x, Arithmetic2 y);
      		 (A)(since C++11)
      (constexpr since C++23)
      1) Determines if the floating point numbersx andy are unordered, that is, one or both are NaN and thus cannot be meaningfully compared with each other. The library provides overloads for all cv-unqualified floating-point types as the type of the parametersx andy.(since C++23)
      A) Additional overloads are provided for all other combinations of arithmetic types.

      Contents

      [edit]Parameters

      x, y - floating-point or integer values

      [edit]Return value

      true if eitherx ory is NaN,false otherwise.

      [edit]Notes

      The additional overloads are not required to be provided exactly as(A). They only need to be sufficient to ensure that for their first argumentnum1 and second argumentnum2:

      • Ifnum1 ornum2 has typelongdouble, thenstd::isunordered(num1, num2) has the same effect asstd::isunordered(static_cast<longdouble>(num1),
                         static_cast<longdouble>(num2))        .
      • Otherwise, ifnum1 and/ornum2 has typedouble or an integer type, thenstd::isunordered(num1, num2) has the same effect asstd::isunordered(static_cast<double>(num1),
                         static_cast<double>(num2))        .
      • Otherwise, ifnum1 ornum2 has typefloat, thenstd::isunordered(num1, num2) has the same effect asstd::isunordered(static_cast<float>(num1),
                         static_cast<float>(num2))        .
      		(until C++23)

      Ifnum1 andnum2 have arithmetic types, thenstd::isunordered(num1, num2) has the same effect asstd::isunordered(static_cast</*common-floating-point-type*/>(num1),
                       static_cast</*common-floating-point-type*/>(num2))      , where/*common-floating-point-type*/ is the floating-point type with the greatestfloating-point conversion rank and greatestfloating-point conversion subrank between the types ofnum1 andnum2, arguments of integer type are considered to have the same floating-point conversion rank asdouble.

      If no such floating-point type with the greatest rank and subrank exists, thenoverload resolution does not result in a usable candidate from the overloads provided.

      		(since C++23)

      [edit]Example

      Run this code
      #include <cmath>#include <iostream> #define SHOW_UNORDERED(x, y) \    std::cout << std::boolalpha << "isunordered(" \              << #x << ", " << #y << "): " \              << std::isunordered(x, y) << '\n' int main(){    SHOW_UNORDERED(10,01);    SHOW_UNORDERED(INFINITY,NAN);    SHOW_UNORDERED(INFINITY,INFINITY);    SHOW_UNORDERED(NAN,NAN);}

      Output:

      isunordered(10, 01): falseisunordered(INFINITY, NAN): trueisunordered(INFINITY, INFINITY): falseisunordered(NAN, NAN): true

      [edit]See also

      (C++11)
      		 categorizes the given floating-point value
      (function)[edit]
      (C++11)
      		 checks if the given number is NaN
      (function)[edit]
      C documentation forisunordered
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