hopefully pointing in the right direction

[Totes my goat]

Hey Y'all, I just finished a homework assignment and was hoping to get another set of eyes to glance over it and make sure I did everything. I would really appreciate it! I am suppose to

1) create a pointer, initialize it to the beginning of the array data
2) output the elements of data by indexing data using a loop.
3) output the elements of data by indexing your pointer using a loop
4) output the elements of data by incrementing the pointer each time through the loop. Your loop control could look like (why does this work?): for (p=data; p < data+5; p++)
5)reset your pointer to point at the beginning of the array again, then output the elements of data by adding i, a loop counter, to the pointer and dereferencing the summed address. Use something like: cout << *(p+i)


Heres my code:

#include <iostream>
using namespace std;

int main()
{
    int i = 5;
    int data[5] = {10, 20, 30, 40, 50};
    char my_cstring[8] = "the fox";
    
    int *p = NULL;
    char *pc = NULL;
    
    p = &data[0];
	
	for(int a=0; a<5; a++)
	{
		cout << data[a] << " ";
	}
	cout << endl; 

	for(int b=0; b<5; b++)
	{
		cout << p[b] << " ";
	}
	cout << endl; 

	for (p=data; p < data+5; p++)
	{
		cout << *p << " ";
	}
	cout << endl;

	p = &data[0];
	for (int i=0; i<5; i++)
	{
		cout << *(p+i) << " ";
	}
	cout << endl;

    cout << "done"<<endl;
    #ifdef WIN32
    system("pause");
    #endif
    return 0;
}

Thanks!

[MikeyBoy]

create a pointer, initialize it to the beginning of the array data

p = &data[0];

That's one way of doing it. However, the name of an array is already a pointer to the first element of the array, so you can simply do:

p = data;

(why does this work?): for (p=data; p < data+5; p++)

It works because, as I said, the name of an array is also a pointer to the first element of the array. The rest is just normal pointer arithmetic.

What are the variables i (at line 6) and my_cstring (at line 8) for? I don't see them being used anywhere. Note that the variable i you declare at line 34 hides the one declared at line 6.

Apart from that, your code looks OK.

I'd recommend getting into the habit of being consistent with your indentation - this will help you a lot when you write more complicated code.

Also, it's better to define const variables, rather than using magic numbers. Consider your use of 5 in this program. Imagine if your teacher suddenly said to you, "Sorry, your array should have 10 elements, not 5." You'd have to go and change it everywhere. If, instead, you'd done:

const int ArraySize = 5;

int main()
{
    int i = ArraySize ;
    int data[ArraySize ] = {10, 20, 30, 40, 50};
    char my_cstring[8] = "the fox";
    
    int *p = NULL;
    char *pc = NULL;
    
    p = &data[0];
	
    for(int a=0; a<ArraySize ; a++)
    {
        cout << data[a] << " ";
    }

// etc... 

Then all you'd have to do is change the value of ArraySize, and it would all still work.