std::linear_congruential_engine<UIntType,a,c,m>::operator()
From cppreference.com
                    
                                        
                    < cpp | numeric | random | linear congruential engine
                    
                                                            
                    
|   result_type operator()();  | 
(since C++11) | |
Advances the state of the engine, and generates a pseudo-random value from the new state.
Return value
A pseudo-random number in [min(), max()].
Complexity
Amortized constant.
See also
|   advances the engine's state by a specified amount  (public member function)  |