how to get type information in C++
Hi Masters:
i have a question about how does compiler know the type information.
e.g.
class A{};
A* p;
when we need to dereference p, or such like ++p, the pointer arithmetic, how does compiler know how much amount to move ahead? or, how does the compiler to get the type information?
my naive understanding is:
p stores a machine word, and that's all p has.
form only p's content(a machine word), compiler can not deduce what is p.
So how does compiler knows what type is p?
is there a table or something?
thanks.
i have a question about how does compiler know the type information.
e.g.
class A{};
A* p;
when we need to dereference p, or such like ++p, the pointer arithmetic, how does compiler know how much amount to move ahead? or, how does the compiler to get the type information?
my naive understanding is:
p stores a machine word, and that's all p has.
form only p's content(a machine word), compiler can not deduce what is p.
So how does compiler knows what type is p?
is there a table or something?
thanks.
The compiler knows everything since it sees your source code.
It obviously can see that p is a pointer-to-A since it parsed the declaration
A* p;
It obviously can see that p is a pointer-to-A since it parsed the declaration
A* p;
What the compiler 'sees'and what the compiler 'generates' are very different and I suspect you are confusing the two.
The compiler sees the type information. The source code is required to include it and the compiler's job is to keep a note of every type so that it can allocate the right amount of space and do correct pointer arithmetic.
The compiler sees the type information. The source code is required to include it and the compiler's job is to keep a note of every type so that it can allocate the right amount of space and do correct pointer arithmetic.
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