std::clock_t
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header  <ctime>
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|   typedef /* unspecified */ clock_t;  | 
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Arithmetic type capable of representing the process running time of implementation-defined range and precision.
See also
|   returns raw processor clock time since the program is started  (function)  | |
|   number of processor clock ticks per second  (macro constant)  | |
|   C documentation for clock_t 
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