Question

Why is *(ptra + 0).prop not valid and (*(ptra + 0)).prop valid ? . I know that left side of the dot operator must have a structure. But I am still confused. Could someone explain to me the difference between the two ?

class myobj 
{
public:
    int v;
};

int main()
{

    myobj *ptra = new myobj[2]();

    *(ptra + 0).v = 12 //Error

    (*(ptra + 0)).v = 12 ; //OK

    return 0;

}

Answer 1

Because operator . has a higher precedence then operator * , so

*(ptra + 0).v

means

*((ptr + 0).v)

and not

(*(ptra + 0)).v

*((ptr + 0).v) here is incorrect syntax, because (ptr + 0) is not a class or union, so has no any members.