// A few common random functions. (1.04)
 
#include <stdexcept>
#include <random>
#include <algorithm>
#include <experimental/iterator>
#include <iostream>
using namespace std;
 
// Initialize generator with non-deterministic seed.
 
static thread_local default_random_engine re_(random_device{}());
 
// Real uniformly distributed on the interval [0, 1).
 
double randreal()
{
    uniform_real_distribution<double> pick(0, 1);
    return pick(re_);
}
 
// Integer uniformly distributed on the closed interval [lo, hi].
 
int randint(int lo, int hi)
{
    if (!(lo <= hi))
        throw invalid_argument("lo must be less than or equal to hi");
    uniform_int_distribution<> pick(lo, hi);
    return pick(re_);
}
 
// Boolean where the probability of true is p and false is (1-p).
 
bool randbool(double p)
{
    if (!(0.0 <= p && p <= 1.0))
        throw invalid_argument("p must be between 0 and 1 (inclusive)");
    bernoulli_distribution pick(p);
    return pick(re_);
}
 
// Main.
 
template<typename Func, typename... Args>
void display(int n, Func f, Args... args)
{
    cout << '[';
    generate_n(experimental::make_ostream_joiner(cout, ", "), n,
               [=]{ return f(args...); });
    cout << "]\n";
}
 
int main()
{
    display(10, randreal);
    display(10, randint, -5, 5);
    display(10, randbool, 0.5);
}

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