Can't understand the outcome! help

[hilft]

I do not understand why my compiler gives me 21 when I run the code below.
From my understanding, it should give me 12. Can anyone explain me why?

Side note)
If it use: cout << a.get();
cout << b.get(); it gives me 12.

    #include <iostream>
    using namespace std;
    
    class A { 
        int *val;
    public:
        A() { val = new int; *val = 0; }
        int get() { return ++(*val); } 
    };
    
    int main() {
        A a,b = a;
        cout << a.get() << b.get();
        return 0;
    }

[cire]

The order in which a.get() and b.get() are evaluated on line 13 is unspecified by the standard. Either 21 or 12 would be correct output.