Question

I am relatively new to C++ and am having problems understanding struct.

I have a struct declared as follow

struct MyNode {
    int level;
    int index;
    MyNode children[4];
}

However the code fails to compile and reports error C2148: total size of array must not exceed 0x7fffffff bytes.

But the following code compiles

struct MyNode {
    int level;
    int index;
    MyNode* children;
}

Can i code MyNode as in the first example or is there something that I am missing.

Thanks!

Answer 1

This fails to compile, because the compiler needs to know the size of each type.
So, what’s sizeof(MyNode) ? It’s sizeof(int) * 2 + sizeof(MyNode) : The recursion makes the size impossible to figure out.

You need a pointer, as in your second example. Why does this works ? Because sizeof(MyNode*) is known : it’s the size of an address on the target platform.