sysrap/tests/random.cc

0001 // name=random ; gcc $name.cc -std=c++11 -lstdc++ -o /tmp/$name && /tmp/$name
0002 /**
0003 https://stackoverflow.com/questions/9878965/rand-between-0-and-1
0004
0005 https://stackoverflow.com/questions/31417957/encapsulated-random-number-generator-in-c-11-using-boost
0006
0007 **/
0008 #include <iostream>
0009 #include <iomanip>
0010 #include <random>
0011
0012
0013
0014 int main()
0015 {
0016     std::mt19937_64 rng;
0017
0018     unsigned seed = 0u ;
0019     rng.seed(seed);
0020     std::uniform_real_distribution<double> unif(0, 1);
0021
0022     double a ;
0023     double b ;
0024     bool done ;
0025     unsigned count = 0 ;
0026
0027     do {
0028         a = unif(rng);
0029         b = unif(rng);
0030         std::cout
0031             << " count " << std::setw(10) <<  count
0032             << " a " << std::fixed << std::setw(10) << std::setprecision(4) <<  a
0033             << " b " << std::fixed << std::setw(10) << std::setprecision(4) <<  b
0034             << std::endl
0035             ;
0036
0037         done = a > 0.99 && b > 0.99 ;
0038         count += 1 ;
0039
0040     } while( done == false ) ;
0041
0042
0043     std::cout
0044         << " result "
0045         << " count " << count
0046         << " a " << a
0047         << " b " << b
0048         << std::endl
0049         ;
0050
0051     return 0;
0052 }
0053
0054