import std.algorithm;

import std.random;

import std.range;

import std.stdio;

​

void main()

{

    foreach (numSamples; iota(0, 1000+1, 100).filter!(n => n > 0))

    {

        auto samples = new double[numSamples];

        enum objectStart = 0.25;

        enum objectEnd   = 0.75;

​

        enum numTotalSamples = 10_000_000;

        auto numSizes = numTotalSamples / numSamples;

        auto sizes = new double[numSizes];

        foreach (ref size; sizes)

        {

            size_t numHits;

            foreach (i; 0 .. numSamples)

            {

                auto sample = uniform01!double;

                if (sample >= objectStart && sample < objectEnd)

                    numHits++;

            }

​

            size = 1.0 / numSamples * numHits;

        }

​

        sizes.sort;

        writef("%d samples:", numSamples);

        foreach (certainty; [50, 90, 99])

        {

            auto centerDist = numSizes * certainty / 100 / 2;

            auto startPos = numSizes / 2 - centerDist;

            auto endPos   = numSizes / 2 + centerDist;

            writef("\t%.5f..%.5f", sizes[startPos], sizes[endPos]);

        }

        writeln;

    }

}

​