std::islessgreater
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header  
<cmath>
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|   bool islessgreater( float x, float y ); 
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(since C++11) | |
|   bool islessgreater( double x, double y ); 
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(since C++11) | |
|   bool islessgreater( long double x, long double y ); 
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(since C++11) | |
Determines if the floating point number x is less than or greater than the floating-point number y, without setting floating-point exceptions.
Contents | 
[edit] Parameters
| x | - | floating point value | 
| y | - | floating point value | 
[edit] Return value
true if x < y || x > y, false otherwise
[edit] Notes
The built-in operator< and operator> for floating-point numbers may raise FE_INVALID if one or both of the arguments is NaN. This function is a "quiet" version of the expression x < y || x > y.
[edit] See also
|    (C++11) 
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   checks if the first floating-point argument is less than the second  (function)  | 
|    (C++11) 
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   checks if the first floating-point argument is greater than the second  (function)  |