Array of different types

Question

C++

I need an array of pointers to different types of data.( like in python ). I suppose, that it can be done with templates. Please, depict it shortly in words ( i want to code it by myself)

Answer 1

Here for example:

https://www.laurentluce.com/posts/JUMP_LINK__&&__python__&&__JUMP_LINK-list-implementation/

Answer 2

It can be a cool exercise and all but here's why mixed-type arrays are not useful:

- Arrays can be of any length.
- The only way to run through a whole array is using a loop.
- In the loop body, we are running the same block of code for each element.
- To make that work, every element needs to be of the same type.

That's not to say that we can't have multiple types in an array. But variable types + variable length is not helpful / nonsensical.

We can fix the set of types, like so:
union many_types {
int a;
float b;
char c;
}

std::vector<many_types> arr;

Or we can fix the length, like so:

std::tuple<int, float, char> tup;

It's an either/or situation. You can have arbitrary types with fixed length, or arbitrary length with fixed types, but not both.

Answer 3

Why do you (think you) need it?

Can you describe your situation?

Because there might be a more natural way.

Answer 4

You may find answer in https://realpython.com/pointers-in-JUMP_LINK__&&__python__&&__JUMP_LINK/
and in https://overiq.com/c-programming-101/array-of-pointers-in-c/

Answer 5

i read , that in python it is realised via pointers, thus i think , that its the most simple way
Originally task was to make an array of any type via templates, but i decided to improve it a bit

Answer 6

Did they actually mean, that your array should work for mixed types, or that it should work for *one* version of the template, like vector<int> for example?

Answer 7

yes, only for one version. But I decided to know how to make for multiple types

Answer 8

Just to make sure:

You want to have an int at spot 0, a char at spot 1, a double at spot 2...

Answer 9

yes

Answer 10

oh, thanks a lot

Answer 11

Hm. I think there was some homepage where the algo Python uses is described.

Python's written in C after all.

Now where did I see that...

Answer 12

It might be 'slightly' harder than the original task though! 🤣

Good luck!

Answer 13

Zandi - kurdish Programmer, can you explain the relationship of your answer to the question?