reinterpret_cast vector of class A to vector of class B

Question

Say I have two classes A and B, and a vector of class A as below:

class A {
    int foo;
    int bar;
    void someMet         


        

Answer 1

The program behaviour is undefined since the types are unrelated.

One solution is to write a cast operator to copy a class B instance to a class A instance. In class B, write

operator A() const
{
    A a;
    a.foo = this->foo; // ToDo - check `this->foo` is an appropriate size
    a.bar = this->bar; // ToDo - check `this->bar` is an appropriate size
    return a; // compiler will elide the value copy
}