Help with a program

[Ric]

I need help with creating a program that defines an array of five integers and a pointer to an integer.

-The pointer needs to point to the beginning of the array.
-The area needs to be filled with values using the pointer. The array name can't be used.
-The pointer subscript notion must be used to print out the array.

Thank you in advance if anyone can help.

Here is what I have so far:

int main()
{
    int a[5];
    int *ptr_arr;
    ptr_arr = &a[0];
    for (int i = 0; i < 5; i++)
    {
        cout << "Enter array value: " << endl;
        cin >> *ptr_arr;
        ptr_arr++;
    }
    cout << "The beginning of the array is: " << ptr_arr << endl;
    return 0;
}

[Ganado]

What specifically do you need help with?
http://www.cplusplus.com/doc/tutorial/

Your assignment is to forget that the arr[i] operator exists--for some asinine reason (not your fault)--and to use *(arr + index) notation instead.

[Ric]

I need help with creating a program that has all of those things I listed above.

[doug4]

Can you show us what you have so far? Nobody here wants to do your homework for you.

Also, my interpretation of your assignment is slightly different that @Ganado's.

The 2nd bullet point just says that the array name cannot be used when populating the array. This can be done in any of the following ways:

ptr[i] = x;
*(ptr + i) = x;
*(ptr++) = x;

The 3rd bullet point requires the use of subscript notation. This can be done in either of the following ways:

std::cout << arr[i];
std::cout << ptr[i];

I left a lot of hints here. Write some code, and let us know where you have problems. Make sure you post the code that you write, and use code tags. (click the "<>" format button and paste your code between the generated tags.)

[Ric]

This is what I have so far:

int main()
{
    int a[5];
    int *ptr_arr;
    ptr_arr = &a[0];
    for (int i = 0; i < 5; i++)
    {
        cout << "Enter array value: " << endl;
        cin >> *ptr_arr;
        ptr_arr++;
    }
    cout << "The beginning of the array is: " << ptr_arr << endl;
    return 0;
}

[doug4]

Please edit your previous post and add code tags. Highlight the code that you pasted and click the "<>" format button.

Using code tags makes it easier to read and review your code.

Beyond that, what are you trying to do with this line?
int (*ptr)[5];

The following lines from your code do the first bullet point:

int main()
{

    int *p;
    int arr[5];
    p = arr;

    return 0; 
}

The rest of the lines are pretty much meaningless. You can probably get rid of them.

Next you need to do bullet point 2. Populate the values in the array using your pointer p.

I assume the class you are taking is in C because your print statements are not C++ code.

[Ric]

Edited my previous post and my OP. Sorry, that thing I copied there was the wrong code.

[deleted account xyzzy]

Line 12, you are printing out the address of the SIXTH element in your 5 element array. You are going out of bounds by incrementing 5 times in your for loop (0 -5).

#include <iostream>

int main()
{
   int arr[5];

   // int* ptr_arr;
   // ptr_arr = &arr[0];

   // the name of an array is an address (pointer) to the first element
   // int* ptr_arr = arr;

   int* ptr_arr { arr };

   for (size_t i = 0; i < 5; i++)
   {
      std::cout << "Enter array value: ";
      std::cin >> *(ptr_arr + i);
   }
   std::cout << '\n';

   // are you sure you want the first element's address?
   std::cout << "The beginning of the array is: " << ptr_arr << ".\n\n";

   for (size_t i = 0; i < 5; i++)
   {
      // must use pointer subscript!  ooops!
      std::cout << ptr_arr[i] << ' ';
   }
   std::cout << '\n';
}

Enter array value: 3
Enter array value: 6
Enter array value: 9
Enter array value: 12
Enter array value: 15

The beginning of the array is: 008FFA00.

3 6 9 12 15

[Ric]

Thanks a lot. I appreciate it.

[eyssant]

#include <iostream>
using namespace std;
int main()
{
    int a[5];
    int *ptr_arr;
    ptr_arr = a;
    for (int i = 0; i < 5; i++)
    {
        cout << "Enter array value: " << endl;
        cin >> *ptr_arr;
        ptr_arr++;
    }
    cout << "The beginning of the array is: " << ptr_arr << endl;
    return 0;
}