c++: at what point should I start using "new char[N]" vs a static buffer "char[Nmax]"
- by dan
My question is with regard to C++
Suppose I write a function to return a list of items to the caller. Each item has 2 logical fields: 1) an int ID, and 2) some data whose size may vary, let's say from 4 bytes up to 16Kbytes. So my question is whether to use a data structure like:
struct item {
int field1;
char field2[MAX_LEN];
OR, rather, to allocate field2 from the heap, and require the caller to destroy when he's done:
struct item{
int field1;
char *field2; // new char[N] -- destroy[] when done!
Since the max size of field #2 is large, is makes sense that this would be allocated from the heap, right? So once I know the size N, I call field2 = new char[N], and populate it.
Now, is this horribly inefficient?
Is it worse in cases where N is always small, i.e. suppose I have 10000 items that have N=4?
