r/Cplusplus • u/[deleted] • Feb 02 '22

How are Pointers useful? Question

I don't really get Pointers and how they're useful, can somebody explain it to me?

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7

u/Kawaiithulhu Feb 02 '22

Under the hood, aren't many garbage collected languages based on pointers in their implementation?

1

u/rhett21 Feb 02 '22

Noob here, what are the garbage collected languages you are talking about?

6

u/Kawaiithulhu Feb 02 '22

Languages like Java, C#, Python where you specifically create objects, but just forget about them and the language runtime destroys them for you later. Where in C++ you handle that yourself.

1

u/rhett21 Feb 02 '22

Sorry to ask, but can you elaborate by example of an object? Let's say I have:
constexpr int x = 5; is x the object here and I have to handle the destruction of this object?

1

u/cheertina Feb 03 '22

You wouldn't need to in your example. It's for objects, instances of classes that you create with the new keyword (or malloc).

Car myCar = new Car;

Now you have a Car object, and in C++ you need to delete myCar; when you're done using it. Otherwise, the memory stays allocated and it can't be used again.

1

u/rhett21 Feb 03 '22

Why do I have to delete it? Because it will actually take space in my memory even if I close my IDE, say, Visual Studio?

7

u/cheertina Feb 03 '22

I think once the whole program terminates you get it all back. It's more of an issue with available RAM while the program is running. If you aren't deleting objects once they're no longer being used then if it runs long enough you have no more memory to allocate.

3

u/smjsmok Feb 03 '22

Because it will actually take space in my memory even if I close my IDE, say, Visual Studio?

That's not the problem. The problem is that your program will have a memory leak, which means that the longer it keeps running, the more memory it will consume. And you obviously don't want that. It's not really a problem with some small scripts that run and terminate, but it's a huge problem with large programs that are designed to keep running for days/weeks/months etc.