std::abs(int), std::labs, std::llabs, std::imaxabs
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header <cstdlib>
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|   int       abs( int n );  | 
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|   long      abs( long n );  | 
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|   long long abs( long long n );  | 
(since C++11) | |
|   long       labs( long n );  | 
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|   long long llabs( long long n );  | 
(since C++11) | |
|   Defined in header <cinttypes>
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|   std::intmax_t abs( std::intmax_t n );  | 
(since C++11) | |
|   std::intmax_t imaxabs( std::intmax_t n );  | 
(since C++11) | |
Computes the absolute value of an integer number.
[edit] Parameters
| n | - | integer value | 
[edit] Return value
the absolute value of n (i.e. |n|)
[edit] See also
|    absolute value of a floating point value (|x|)   (function)  | |
|    returns the magnitude of a complex number   (function template)  | |
|    applies the function std::abs to each element of valarray   (function template)  | |