十八、How many prime numbers

Problem Description
Give you a lot of positive integers, just to find out how many prime numbers there are.

Input
There are a lot of cases. In each case, there is an integer N representing the number of integers to find. Each integer won’t exceed 32-bit signed integer, and each of them won’t be less than 2.

Output

For each case, print the number of prime numbers you have found out.《开方函数和一次整除 对时间很重要》

Sample Input
3
2 3 4

Sample Output
2

#include <iostream>#include<cmath>using namespace std;int main( ){    int n,k,m,j,i,x;    while(cin>>n)    {   x=0;       for(i=0;i<n;i++)       { k=0;           cin>>m;           for(j=2;j<=sqrt(m);j++)            if(m%j==0) {k++;break;}            if(k==0) x++;       }         cout<<x<<endl;    }    return 0;}