Member function of a nonexistent object

#include <cstdio>

class C{
public:
    int x;
    void f(){
        printf("\nHello world!\n");
        printf("this == %p\n", this);
        printf("x == %d\n", x);
    }
};

int main(){
    C c;
    c.f();

    C *p = reinterpret_cast<C*>(0xfe58648); //nonsense address
    p->f();
}

//Output:

Hello world!
this == 0x7fff656e3a40
x == 0

Hello world!
this == 0xfe58648
Segmentation fault: 11