Nested structures

c, struct

Solution

The code in your post is obviously incomplete, just declarations, so it is hard to say anything conclusive.

On obvious difference is that in C++ the inner struct type will be a member of outer struct type, while in C language both struct types will be members of the same (enclosing) scope. (BTW, was it your intent to declare them locally in `main`?).

In other words, in C++ the code that follows would have to refer to the structs as `xx` and `xx::yy`, while in C they would be just `xx` and `yy`. This means that the further code would look different for C and C++ and if it will compile in C++, it wouldn't compile in C and vice versa.

Added: C language prohibits declaring struct types inside other structs without declaring a member of that type. So, you `struct yy` declaration is illegal in C and will produce compiler diagnostic message. If you wanted your code to become legal in both C and C++, you'd have to combine the `struct yy` declaration with some data member declaration. In your case that could be pointer `q`:

struct xx {
        int x;
        struct yy {
                char s;
                struct xx *p;
        } *q;
};

The above is legal in both C and C++ (taking into account the differences I explained earlier), but your original declaration is not legal in C.

Problem

The following code compiles on a C++ compiler. ``` #include <cstdio> int main() { struct xx { int x; struct yy { char s; struct xx *p; }; struct yy *q; }; } ``` Would there be any difference in behavior while compiling with a C compiler? i.e. would there be any compiler error?

Original source