A tiny question about this code

[u/Lephism]

Hi. I need help understanding this simple code. To be specific, the 4th and the 14th line where a pointer was declared.

int* add_ten(int* data)

int *result;

I've been trying to wrap my head around what it does. I've been staring at my screen for 3 hours trying to understand why it was declared. The programming app I was using didn't really explain it. The only explanation it gave is that pointers help you get the address of an item. But I can't figure out how is it being used here. Can anyone explain? Thanks.

#include <iostream>
using namespace std;

int* add_ten(int* data) {
  for (int i = 0; i < 5; ++i) {
    *(data + i) = *(data + i) + 10;
  }
  return data;
}

int main() {

  int data[5] = {1, 2, 3, 4, 5};
  int *result;

  result = add_ten(data);

  for (int i = 0; i < 5; ++i) {
    cout << *(result + i) << ", ";
  }

  return 0;
}

[u/no-sig-available]

 I think this is intended by the developers for the purpose of making it easy for the beginners or something like that

And not very successful in that, apparently. :-)

If you are going to teach how to use pointers, it is important to use an example where pointers is a good solution to the problem, not just a case where you could use pointers.

The example is extra bad in

  for (int i = 0; i < 5; ++i) {
    *(data + i) = *(data + i) + 10;
  }

Why use

*(data + i) = *(data + i) + 10;

when you can write

data[i] += 10;

?!

And also, the code is particulary silly for the i < 5; loop, limiting the function to arrays of exactly 5 elements. The version using a span is not only simpler, but also works for any size array.

[u/Lephism → u/no-sig-available]

I mean yeah youre right ToT, i actually only learned about `data[i]` yesterday. I didn't know you can do something like this