c++打印数字三角

int main()
{
    int n = 9;  // 这里控制打印几层
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j < n - i + 1; j++) {
            cout << " ";
        }
        for (int j = 1; j < i; j++) {
            cout << j;
        }

        for (int j = i; j > 0; j--) {
            cout << j;
        }
        cout << endl;
    }

    //system("pause");
    return -1;

}