Question

I’ve asked a similar question on structs here but I’m trying to figure out how C handles things like assigning variables and why it isn’t allowed to assign them to eachother if they are functionally the same.

Lets say I have two arrays:

int x[10];   int y[10];   

Why won’t x = y compile? If they are both the same ‘signature’ like that, then shouldn’t you be able to assign them back and forth?

Can I declare these in a way that would allow me to do that in C? It makes sense to me that you would be able to, but maybe there is a way that this can be done? Typedefs for structs seemed to be the solution, would it be the same for array declaration and assignment?

I appreciate your guys help, I’m new to Stackoverflow but it has been a really good resource for me so far!

Answer 1

Simply put, arrays are not assignable. They are a ‘non-modifiable lvalue’. This of course begs the question: why? Please refer to this question for more information:

Why does C++ support memberwise assignment of arrays within structs, but not generally?

Arrays are not pointers. x here does refer to an array, though in many circumstances this ‘decays’ (is implicitly converted) to a pointer to its first element. Likewise, y too is the name of an array, not a pointer.

You can do array assignment within structs:

struct data {     int arr[10]; };  struct data x = {/* blah */}; struct data y; y = x; 

But you can’t do it directly with arrays. Use memcpy.