求素数

#include <iostream>
#include <math.h>
using namespace std;
bool IsPrime(int n)
{
	int i, j;
	
	if (n == 2)
	{
		return true;
	}
	else if (n < 2 || n%2==0)
	{
		return false;
	}
	else
	{
	  	j = (int)sqrt(n + 1);
		for (i = 3; i <= j; i = i + 2)
		{
			if (n % i == 0)
			{
				return false;
			}
		}
	}
	return true;
}
int PrintPrim(int n)
{
	assert(n >= 7);
	unsigned int *array = (unsigned int *)malloc(n*sizeof(unsigned int));
	assert(array != NULL);
	
	int k = 0;
	array[k++] = 2;
	array[k++] = 3;
	array[k++] = 5;
	array[k++] = 7;
	for(int i=11; i<=n; i++)
	{
		if(i%2==0 || i%3==0 || i%5==0 || i%7==0) continue;
		array[k++] = i;
	}
	
	int iCount = 4;
	for(int i=5; i<k; i++)
	{
		if(true == IsPrime(array[i])) array[iCount++] = array[i];
	}
	for(int i=0; i<k; i++)
	{
		//cout << i << ":" << array[i] << "\n";
		cout << array[i] << "\t";
	}
	free(array);
	return k;
}
int main(int argc, char *argv[])
{
	PrintPrim(1000);
	return 0;
}