import std.conv, std.datetime, std.random, std.range, std.stdio;
import std.math: isNaN;

struct S
{
    bool b;
    double d;
}

void main()
{
    auto arr = new S[1_000_000];
    size_t count = 100 * arr.length;

    foreach (ref a; arr)
    {
        a.b = false;
        a.d = double.nan;
    }

    auto sample = randomSample(iota(arr.length), 1 * arr.length / 10);
    foreach (s; sample)
    {
        arr[s].b = true;
        arr[s].d = double.infinity;
    }

    StopWatch watch;
    size_t i = 0;

    watch.start();
    foreach (a; cycle(arr).take(count))
    {
        if (!a.b)
        {
            ++i;
        }
    }
    watch.stop();

    real timeBool = to!real(watch.peek.usecs);
    writeln("Time for ", count, " if(boolean)'s with ", i, " counts of true: ", timeBool, " microseconds [", timeBool / count, " per test].");

    watch.reset;
    i = 0;

    watch.start();
    foreach (a; cycle(arr).take(count))
    {
        if (isNaN(a.d))
        {
            ++i;
        }
    }
    watch.stop();

    real timeNaN = to!real(watch.peek.usecs);
    writeln("Time for ", count, " if(isNaN)'s with ", i, " counts of true: ", timeNaN, " microseconds [", timeNaN / count, " per test].");
    writeln;
    writeln("Total difference: ", timeBool - timeNaN, " [", (timeBool - timeNaN) / count, " per test].");
}