Shallow Copy Shares the Buffer

1#include <iostream>
2using namespace std;
3 
4class Shallow {
5public:
6    int* value;
7    Shallow(int v) { value = new int(v); }
8    // no copy constructor: the compiler copies the pointer itself
9};
10 
11class Deep {
12public:
13    int* value;
14    Deep(int v) { value = new int(v); }
15    Deep(const Deep& other) { value = new int(*other.value); }
16};
17 
18int main() {
19    Shallow s1(5);
20    Shallow s2 = s1;
21    *s2.value = 9;
22    cout << *s1.value << " " << *s2.value << endl;
23 
24    Deep d1(5);
25    Deep d2 = d1;
26    *d2.value = 9;
27    cout << *d1.value << " " << *d2.value << endl;
28 
29    cout << (s1.value == s2.value) << " " << (d1.value == d2.value) << endl;
30    return 0;
31}