Pointers, how i hate you

[jerimo]

I tried doing this

Current->Next = New_Cur;

Next is a pointer, of type node. New_Cur is a const pointer of type node. For some odd reason the compiler is hollering that it can not do this.
Now question time; Is there an easy way of making the pointer equal to a const pointer?

The exact error is:

C:\...\Programming\Comp_Engine\SYSTEM\Entity_Lists.cpp|20|error: invalid conversion from 'const comp_node*' to 'comp_node*' [-fpermissive]|

[rcgldr]

The compiler seems to be complaining about using a pointer to a constant node (const node *), not a constant pointer to node (node * const).

[iMalc]

Yes it's possible to force it to accept this, but it is generally a mistake. Const wouldn't be very robust if you could just take some pointer-to-const, assign that to a pointer-to-non-const, and then just write away over that data without worries. Const is meant to stop that.

Probably either Next should be "const comp_node*", or New_Cur should be just "comp_node*".

And finally, make sure you learn the difference between

const comp_node *x;
//and
comp_node *const x;

so that you can know for sure that you are using the one you intended to be using.

[jerimo]

Oh! thanks iMalc. I had never realised that there were two types of const calls in pointers! Good to know, and thanks again!

[King Mir]

There's also comp_node const * x, which is identical to const comp_node * x.