Question

I would like to build a function that takes a multidimensional array and prints it like a grid. I’m having trouble with it because c++ doesn’t allow a function to have a multidimensional array argument unless you specify its length. There is a question about it on here, that was answered using vectors. I haven’t learned how to use vectors yet, so please don’t use them in an answer, or at least provide a good tutorial on them if you do.

Anyway, I was wondering if it’s possible to return an array in c++… I started programming with javascript, so the first solution I thought of was to do something like

int gen(int len){
    return int arr(int a[][len]){
        cout << a[0][0];
    };
}

I knew it wouldn’t work, tried it, and wasn’t surprised when it didn’t. Is there a way to do something like this though?

Answer 1

In C++ you can pass array by reference. With making an array a template, it’s possible to receive any length in the function. For example,

template<size_t SIZE1>
void print (int (&arr)[SIZE1])
{ ... }

template<size_t SIZE1, size_t SIZE2>
void print (int (&arr)[SIZE1][SIZE2])
{ ... }

template<size_t SIZE1, size_t SIZE2, size_t SIZE3>
void print (int (&arr)[SIZE1][SIZE2][SIZE3])
{ ... }

This pattern will internally create a unique function for every different size of array. It offers ease of use, but may increase the code size.