Newbie Pointer question - An Arrays & and *

Hi,

With this code I am trying to cout the contents and memory location of the array's 'containers'.

Code:

---

#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
        int arrayz[5];
        int *pointername;
        pointername = arrayz;

        for(int t = 0; t<5; t++)
        {
                int randomint = rand();
                arrayz[t] = randomint;
                cout << "Arrayz location " << t << "is " << &pointername[t] << " and value is " << *pointername << endl;
        }
        system("pause");
}

---

During de-bugging, I see random integers being placed into the array as I wanted, but as the screenshot shows below, the cout of the contents are being shown as the same every time.

This is confusing me, as I don't see why they aren't displayed as different, as I know they indeed are.

Any help is greatly appreciated.

Thanks.

EDIT - I have tried adding [t] to the end of *pointername in the cout line, but it fails to compile, but works with &pointername.

your pointername pointer points to the first element of the array - you never update it - so you always print the value of the first element

thanks vart!

I found this, and it does now print the correct memory addresses, but the same technique fails when I add [t] to *pointername.

Code:

---

#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
        int arrayz[5];
        int *pointername;
        pointername = arrayz;

        for(int t = 0; t<5; t++)
        {
                int randomint = rand();
                arrayz[t] = randomint;
                cout << "Arrayz location " << t << "is " << &pointername[t] << " and value is " << pointername[t] << endl;
        }
        system("pause");
}

---

Problem resolved. It doesn't work if you use the * before the arrays name.

Should anyone see any mistakes i am making in this little program, I would love to hear them.

Thanks :)

What's the point of pointername? You could use arrayz in the same way.

If you're testing how pointers can be incremented and used on arrays without the [] syntax, then you would want to increment pointername each time through the loop and dereference it to access the element rather than use [] and t.

OK, I've incremented the pointer, and would welcome any comments on whether I have done this correctly. I am currently unsure on the 'dereferencing' thing mentioned.

Code:

---

#include <iostream>
#include <cstdlib>
#include <cctype>
#include <cstdio>// I realise not all these libraries are not being used.

using namespace std;

int main()
{
        int arrayz[5];
        int *pointername;
        pointername = arrayz;


        for(int i=0; i<5; i++)
        {
                int randomint = rand();
                *pointername = randomint;
                pointername++;
                cout << arrayz[i] << endl;
        }
       
        system("pause");
}

---

Thanks!

This code looks fine. Plus, you are using the pointer with pointer syntax.

Whether or not it is "correct" depends on what the point of the exercise is. You aren't outputting the memory location anymore, so you might consider adding that.

Thanks Daved.

There is no real point to this, I'm just trying to get my head around the subject and the syntax.

Hearing knowledgeable people like yourself say it looks fine is a great.

Thanks for all your help!

>> I'm just trying to get my head around the subject and the syntax.
Ok, then how about you try to change your current code so that it outputs:

"Arrayz location [location] is [address] and value is [value]."

But don't use the arrayz variable anywhere inside the for loop.

A final note. It's very possible to initialize variables on the line they're defined instead of assigning on the second line:

Code:

---

        int *pointername;
        pointername = arrayz;

---

Is the same as

Code:

---

        int *pointername = arrayz;

---