question about pointers, cast

Hello, I've experience programming in C, but am new (somewhat) to C++. Please take a look at this snippet below. I haven't been active in C for a while, but would think it would work without the cast of (<type> *).
Am I remembering wrong, or, since I'm using a C++ compiler (G++, using Dev-C++), is that affecting the results?

Quote:

---

#define BYTE unsigned char
#define ULONG unsigned long int

void POKE (ULONG *, BYTE);
BYTE PEEK (ULONG *);

int main(int argc, char *argv[])
{

int a=5;
ULONG *p_a;
char key;

p_a=(ULONG *)&a;
POKE(p_a, 0xff);

---

As it is, this compiles fine and works as I would expect. And for example, if I code:
p_a=(ULONG *)0x5000

this makes sense to me because I don't actually have an address of a variable for the variable reference operator &, so I should be stating p_a points to a ULONG , and not the value of 0x5000, but the cast by (ULONG *) is the address supplied.

But without the (<type> *) cast, I get an error compiling. Since I have a variable 'a' above (type int), shouldn't:
p_a=(ULONG)&a

suffice? What am I missing here? Am I losing my marbles, or just rusty with this stuff?

Thanks in advance.

Try a better cast:

Code:

---

p_a = reinterpret_cast <ULONG *> (&a);

---

int and unsigned long int are different types, so they need to be typecasted. p_a=(ULONG)&a wouldn't work well since you're trying to cast a pointer into a normal variable. At any rate, take Speedy's adcive and use templated C++ casts instead of old C ones.