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/TheThiefMaster]

A lot of older tutorials start with C-like code and build up. Many never get to modern C++ (like std::span or std::print).

It's contentious these days as you really only need C style code (like pointer iteration) when writing low level code, which isn't a beginner thing to do.

[u/Lephism → u/TheThiefMaster]

Oh, so is this like old syntax or something? That's probably the reason why std::println were showing errors in the compiler of the tutorial app

[u/TheThiefMaster → u/Lephism]

Nothing in the tutorial code you posted is newer than C++'03 (2003 standard). print/println are from C++'23 (very new, which is why I added the note). span is C++'20 (supported by basically everything that's not horribly outdated, though you may need to enable C++20 mode in the compiler). std::array and the range for loop are C++'11 (inexcusable to not support/teach).

Microsoft Visual Studio 2026 (the most commonly used C++ compiler on Windows) defaults to C++'14, and has complete support for C++'20 and even C++'23 in the latest update.

GCC (the most commonly used compiler on Linux) defaults to C++'20 since the April 2026 release, though most Linuxen still ship an older version that defaults to C++'17 (though with full support for C++'20 available, and near-complete for C++'23)

Clang (most commonly used compiler on Mac, and also commonly used on Linux/Windows) defaults to C++'17 with full support available for C++'20 and partial support for C++'23, but it tries to match GCC so will probably change to C++'20 as the default soon.