gistfile1.d

import std.stdio;
import std.c.time;
immutable n = 100000000;

pure int calcPrimes()
{
    int numPrimes=0;
    bool []isPrime = new bool[n];

    for(int x=0; x<n; x++)
    {
        isPrime[x]=true;
    }
    isPrime[0]=false;
    isPrime[1]=false;

    for(int x=0; x<n; x++)
    {
        if(isPrime[x])
        {
            for(int y=2*x; y<n; y+=x)
            {
                isPrime[y]=false;
            }
        }
    }

    for(int x=0; x<n; x++)
    {
        if(isPrime[x])
        {
            numPrimes++;        
        //  printf("Prime: %d\n", x);
        }
    }
    delete isPrime;
    return numPrimes;
}

void main(string[] args)
{
    writeln("My first D program!");
    writeln("This program calculates primes!");
    float a = clock();
    immutable int primes = calcPrimes();
    writeln("Primes found:\t", primes);
    writeln("TimeElapsed:\t", ((clock()-a)/CLOCKS_PER_SEC));
}