一.奇数求余法,列出所有的奇数,然后在判断这些奇数有没有能被整除的小于它自身的奇数,有就不是质数;
#include<iostream>
using std::cout;
using std::endl;
int main() {
cout << "2" << endl;
int digit;
int divisor;
for (digit = 3; digit <= 15; digit += 2)
{
for(divisor= 3;divisor < digit;divisor += 2)
{
if(digit%divisor==0)
{
break;
}
}
if(digit==divisor)
{
cout<<digit<<endl;
}
}
}
return 0;
}