日志9

质数判断

#include<iostream>

#include<cmath>

using namespace std;

int main()

{

long long a,b;

while (cin >> a) {

bool z = true;

if (a == 1) {

cout << "No" << endl;//1不是质数

continue;

}

for (long long i = 2; i <= sqrt(a); i++) {//让数a除i到a的平方根，若余数为零则不是

b = a % i;

if (b == 0) {

cout << "No" << endl;

z = false;

break;

}

}

if (z) {

cout << "Yes" << endl;

}

}

return 0;

}