用C++编写一个判断素数的函数程序

#include
#include
using namespace std;
bool isPrimeNum(int);
int main()
{
int k;
cout<<"please input a number:";
cin>>k;
if(isPrimeNum(k))
cout< else
cout< system("pause");
return 0;
}

bool isPrimeNum(int m)//判断一个数是否是素数的函数
{
int count=0;
for (int i=2;i<=sqrt(m);i++)
{
if(m%i==0)
count++;
}
if (count==0)
return 1;
}

#include
#include
using namespace std;
int main(){
	int i,n;
	int flag;
	while(cin>>n)
    {
        if(n<=0||n==1)
            cout<<"no"<        else
        {
            flag=0;
            for(i=2;i            {
                if(n%i==0)
                {
                    flag++;
                    break;
                }
            }
            if(flag==0) cout<<"yes"<            else cout<<"no"<        }
    }
    return 0;}

#include "math.h"
int sushu(int n)
{
int i;
for (i=2;i<=sqrt(n);++i)
if (n%i==0)
return 0;
return 1;
}
从2开始判断，是就返回1，不是返回0

#include
#include
using namespace std;

int fun(int n)
{
int flag;
int k = (int)sqrt(n);
for(int i = 2; i <= k; i++)
{
flag = 1;
if(n % i == 0)
{
flag = 0;
break;
}
}
return flag;
}

int main()
{
for(int i = 2; i < 1000; i++)
{
if(fun(i))
{
cout< int m;
m++;
if(m % 10 == 0)
cout< }
else
continue;
}
return 0;
}

真难