libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/discard.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <random>
  10
  11 // template <class UIntType, UIntType a, UIntType c, UIntType m>
  12 //   class linear_congruential_engine;
  13
  14 // void discard(unsigned long long z);
  15
  16 #include <random>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20
  21 template <class T>
  22 void
  23 rand0()
  24 {
  25     typedef std::linear_congruential_engine<T, 16807, 0, 2147483647> E;
  26     E e;
  27     e.discard(9999);
  28     assert(e() == 1043618065);
  29 }
  30
  31 template <class T>
  32 void
  33 rand()
  34 {
  35     typedef std::linear_congruential_engine<T, 48271, 0, 2147483647> E;
  36     E e;
  37     e.discard(9999);
  38     assert(e() == 399268537);
  39 }
  40
  41 template <class T>
  42 void
  43 other()
  44 {
  45     typedef std::linear_congruential_engine<T, 48271, 123465789, 2147483647> E;
  46     E e1;
  47     E e2;
  48     assert(e1 == e2);
  49     e1.discard(1);
  50     assert(e1 != e2);
  51     (void)e2();
  52     assert(e1 == e2);
  53     e1.discard(3);
  54     assert(e1 != e2);
  55     (void)e2();
  56     (void)e2();
  57     (void)e2();
  58     assert(e1 == e2);
  59 }
  60
  61 int main(int, char**)
  62 {
  63     rand0<unsigned int>();
  64     rand0<unsigned long>();
  65     rand0<unsigned long long>();
  66
  67     rand<unsigned int>();
  68     rand<unsigned long>();
  69     rand<unsigned long long>();
  70
  71     other<unsigned int>();
  72     other<unsigned long>();
  73     other<unsigned long long>();
  74
  75   return 0;
  76 }