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

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <random>

// template <class UIntType, UIntType a, UIntType c, UIntType m>
//   class linear_congruential_engine;

// void discard(unsigned long long z);

#include <random>
#include <cassert>

#include "test_macros.h"

template <class T>
void
rand0()
{
    typedef std::linear_congruential_engine<T, 16807, 0, 2147483647> E;
    E e;
    e.discard(9999);
    assert(e() == 1043618065);
}

template <class T>
void
rand()
{
    typedef std::linear_congruential_engine<T, 48271, 0, 2147483647> E;
    E e;
    e.discard(9999);
    assert(e() == 399268537);
}

template <class T>
void
other()
{
    typedef std::linear_congruential_engine<T, 48271, 123465789, 2147483647> E;
    E e1;
    E e2;
    assert(e1 == e2);
    e1.discard(1);
    assert(e1 != e2);
    (void)e2();
    assert(e1 == e2);
    e1.discard(3);
    assert(e1 != e2);
    (void)e2();
    (void)e2();
    (void)e2();
    assert(e1 == e2);
}

int main(int, char**)
{
    rand0<unsigned int>();
    rand0<unsigned long>();
    rand0<unsigned long long>();

    rand<unsigned int>();
    rand<unsigned long>();
    rand<unsigned long long>();

    other<unsigned int>();
    other<unsigned long>();
    other<unsigned long long>();

  return 0;
}