What will the following code print?

#include <iostream>

struct A {
    operator int() {
        return 1;
    };
    
    operator double() {
        return 2.0;
    }
};

int main() {
    A a;
    
    int i = a;
    float x = a;
    x += i;
    
    std::cout << x;
}

1
2
3
Runtime error
Compilation error

Explanation

Conversion "a" to the float type is ambiguous. The "double()" operator, in this case, has no advantages over the "int()".
operator
13.3.3 Best Viable Function