#include <iostream>
#include <iomanip>

class A
{
    int a;
    static int f;
public:
    int get_a() {
        return a;
    }
    A (const A &y) {
        std::cin>>a;
        a += y.get_a();
    }
    A () {
        std::cin>>a;
        f = 1;
    }
    ~A () {
        if (f) {
            std::cout<<a<<std::endl;
            f = 0;
        }
    }
};

int A::f=0;



Compilation error
000242.cpp: In copy constructor 'A::A(const A&)':
000242.cpp:14:22: error: passing 'const A' as 'this' argument discards qualifiers [-fpermissive]
   14 |         a += y.get_a();
      |                      ^
000242.cpp:9:9: note:   in call to 'int A::get_a()'
    9 |     int get_a() {
      |         ^~~~~