[C++] 깊은 복사 연산자

#include <iostream>
using namespace std;
 
class A {
    int *p;
public:
    A() {
        p = new int;
        *p = 0;
    }
    ~A() { delete p; }
    A(const A &aa) {
        p = new int;
        *p = *aa.p;
    }
    void setA(int data) { *p = data; }
    int getA()const { return *p; }
    A& operator= (const A &aa) {
        if (this == &aa) { return *this; }
        delete p;
        p = new int;
        *p = *aa.p;
        return *this;
    }
};
void main() {
    A aa;
    A bb;
    aa.setA(90);
    cout << aa.getA() << endl;
    cout << bb.getA() << endl;
 
    bb = aa;
 
    cout << aa.getA() << endl;
    cout << bb.getA() << endl;
}