pointer question

Hello!

I got one code:

Code:

---

int main()
{
    int *test1,a;
   
    test1=&a;
   
    test1[0]=5;
   
    cout<<test1<<endl;
   

    system("PAUSE");
    return 0;
}

---

How is possible that compiler lets me use array test1[0] or something even if the test1 is pointer?

Arrays are just a special case of pointers, that's why.

test1[0] is simply another way of writing *(test1 + 0).

Thanks for the reply.
But what if I write
test[1]=5;

and

cout<<*(test1+1)<<endl;

the program crashes. What's the problem?

Quote:

---

Originally Posted by StGuru

Thanks for the reply.
But what if I write
test[1]=5;

and

cout<<*(test1+1)<<endl;

the program crashes. What's the problem?

---

test1 points to an int. One and only one int. test1 is valid as it points to a. test1 + 1 isn't.

So if I put a[5], then it would work right?

Quote:

---

Originally Posted by StGuru

So if I put a[5], then it would work right?

---

a is neither a pointer nor an array, but an int.

Quote:

---

Originally Posted by laserlight

a is neither a pointer nor an array, but an int.

---

I think he means if he declared it as an array like

int a[5].

Quote:

---

Originally Posted by StGuru

So if I put a[5], then it would work right?

---

Almost. In that case, a becomes a pointer, so you'd have

int a[5];
int* test = a;

You don't need a separate pointer though.

Yes, your right. :-)
I got one task where it was test= new int[5];

If you do that, don't forget to delete[] that memory when you're done with it.

Personally I wouldn't use new if there is a low volume of POD or plain old data involved. Just makes life easier.:wave: