C++ Primer, Fifth Edition

17.4.1. Random-Number Engines and Distribution

The random-number engines are function-object classes (§ 14.8, p. 571) that define a call operator that takes no arguments and returns a random unsigned number. We can generate raw random numbers by calling an object of a random-number engine type:

default_random_engine e;  // generates random unsigned integersfor (size_t i = 0; i < 10; ++i)    // e() "calls" the object to produce the next random number    cout << e() << " ";

On our system, this program generates:

16807 282475249 1622650073 984943658 1144108930 470211272 ...

Here, we defined an object named e that has type default_random_engine . Inside the for, we call the object e to obtain the next random number.

The library defines several random-number ...