我的欧拉工程之路_10

Summation of primes

Problem 10

The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.

Find the sum of all the primes below two million.

素数之和

问题 10

10以下的素数之和是 2 + 3 + 5 + 7 = 17.

求小于200万的所有素数的和.

public class Euler10
{
    public static int[] getPrimeArray(int length)
    {
        int[] prime =new int[length];
        prime[0]=2;
        for(int num=3,lengthTemp=1;lengthTemp!=length;num+=2)
        {
            int i;
            boolean primeFlag=true;
            for(i=3;i<=Math.sqrt(num);i+=2)
            {
                if(num%i==0)
                {
                    primeFlag=false;
                    break;
                }
            }
            if(primeFlag==true)
            {
                prime[lengthTemp]=num;
                lengthTemp++;
            }
        }
        System.out.println("最后一个素数:"+prime[length-1]);
        return prime;
    }
    public static void main(String[] args)
    {
        int[] prime=Euler10.getPrimeArray(148933);
        long sum=0;
        for(int temp:prime)
        {
            sum+=temp;
        }
        System.out.println("sum="+sum);
    }
}