prime2.cpp

prime 判断

#include "iostream.h"
#include "math.h"
void main()
{
	long m,i;
	char yn;
	
do
	{
	cout<<"Please input number"<<endl;
	cin>>m;
	double sqrtm=sqrt(m);
	for (i=2;i<=sqrtm;i++)
	{
		if (m%i==0)
			break;

	}
	if (sqrtm<i)
		cout<<"m is a prime\n";
	else
	cout <<"m isn't a prime\n";
	cout<<"If you want to escape,please enter 'n'! or want please enter 'y'\n";
	cin>>yn;
	}while(yn!='n'&&yn=='y');
}