Spring RTS Engine

Code: Select all

#include <iostream>
#include <ctime>
using namespace std;

int CalculateNumberOfPrimes( int maxprime )
{
    bool *IsPrime = new bool[ maxprime ];
    
    for( int i = 0; i < maxprime; i++ )
    {
        IsPrime[i] = true;
    }
    
    int NumberOfPrimes = 0;
    
    for( int i = 2; i < maxprime; i++ )
    {
        if( IsPrime[i] )
        {
            NumberOfPrimes++;
            for( int j = ( i << 1 ); j < maxprime; j+= i )
            {
                IsPrime[ j] = false;
            }
        }
    }
    
    return NumberOfPrimes;
}

int main( int argc, char *argv[] )
{
    clock_t start = clock();
    
    int NumberOfPrimes = CalculateNumberOfPrimes( 10000000 );
    cout << "number of primes: " << NumberOfPrimes << endl;
    
    clock_t finish = clock();
    double time = (double(finish)-double(start))/CLOCKS_PER_SEC;
    cout << "elapsed time: " << time << endl;
    
    return 0;
}

Code: Select all

using System;

class Primes
{
    public int CalculateNumberOfPrimes( int maxprime )
    {
        bool[] IsPrime = new bool[ maxprime ];
    
        for( int i = 0; i < maxprime; i++ )
        {
            IsPrime[i] = true;
        }
        
        int NumberOfPrimes = 0;
        
        for( int i = 2; i < maxprime; i++ )
        {
            if( IsPrime[i] )
            {
                NumberOfPrimes++;
                for( int j = ( i << 1 ); j < maxprime; j+= i )
                {
                    IsPrime[ j] = false;
                }
            }
        }
        
        return NumberOfPrimes;
    }
}

class EntryPoint
{
    public static void Main()
    {
        System.DateTime start = System.DateTime.Now;
    
       int NumberOfPrimes = new Primes().CalculateNumberOfPrimes( 10000000 );
    
       System.DateTime finish = System.DateTime.Now;
       double time = finish.Subtract( start ).TotalMilliseconds;;
        
       Console.WriteLine( "number of primes: " + NumberOfPrimes );
       Console.WriteLine( "elapsed time: " + ( time / 1000 ) );
    }
}