int N = 0, i = 0;
cout << "请输入一个大于等于2的正整数:";
cin >> N;

for (i = 2; i < N; i++)
    if (N % i == 0) {
        cout << "非质数";
        __________; // 此处填写代码
    }
if (i == N)
    cout << "是质数";