#include <bits/stdc++.h>
using namespace std;
int main() {
	int n;
	cin >> n;
	bool isPrime = true;
	if (n < 2) {
		isPrime = false;
	} else {
		int nn = sqrt(n);
		for (int i = 2; i <= nn; i++){
			if (n % i == 0){
				isPrime = false;
				break;
			}
		}
	}
	if (isPrime) {
		cout << "Yes" << endl;
	} else {
		cout << "No" << endl;
	} 
	cout << (isPrime ? "Yes" : "No") << endl;
	return 0;
}

算了之前的看不懂还是自己打的好懂效果好像一样

#include <bits/stdc++.h>
using namespace std;
int main() {
	int a, ans = 0;
	cin >> a;
	for (int i = 1; i <= a; i++) {
		if (a % i == 0) {
			ans += i / i;
		}
	}
	if (ans == 2) {
		cout << "是素数" << endl;
	} else {
		cout << "不是素数" << endl;
	}
	return 0;
}