C++类的空指针调用成员函数

class A 
{
public:
    void print()
    {
        cout << "hello" << endl;
    }
    void print2()
    {
        cout << "hello" << b << endl;
    }
    int b;
}

int main()
{
  A *a;
  a->print();// 1
  a->print2();// 2
}

答案:
1处不会报错，正常输出 hello
2处会报错，Segmentation fault