How can I output multidimensional array by sending its reference-CodePudding

I need som help outputting the content of this multidimensional array. I'm trying pass the address of the array to the function and let it grab and run thru it.

#include <iostream>

using namespace std;

void LoopDeLoop(int[][] *arr)
{
    for(int k = 0; k < 3; k  )
    {
        for(int j = 0; j < 4; j  )
        {
            cout << arr[k][j];
        }
    }
}

int main() {

    int arr[3][4] = { {1,2,3,4}, {5,6,7,8}, {10,11,12,13} };
    
    LoopDeLoop(&arr);

    return 0;
}

CodePudding user response：

This pattern you are trying to use is old fashioned C.

Modern C way to do it should be more clear for you:

#include <array>
#include <iostream>

using MyArray = std::array<std::array<int, 4>, 3>;

void LoopDeLoop(const MyArray& arr)
{
    for (auto& row : arr) {
        for (auto x : row) {
            std::cout << x << ' ';
        }
        std::cout << '\n';
    }
}

int main()
{
    MyArray arr { std::array { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 10, 11, 12, 13 } };

    LoopDeLoop(arr);

    return 0;
}

https://godbolt.org/z/Mbcjf9bx5

CodePudding user response：

C allows to pass plain array by reference and also automatically deduce dimensions using templates:

Try it online!

#include <iostream>

using namespace std;

template <int Rows, int Cols>
void LoopDeLoop(int const (& arr)[Rows][Cols])
{
    for(int k = 0; k < Rows; k  )
    {
        for(int j = 0; j < Cols; j  )
        {
            cout << arr[k][j];
        }
    }
}

int main() {

    int arr[3][4] = { {1,2,3,4}, {5,6,7,8}, {10,11,12,13} };
    
    LoopDeLoop(arr);

    return 0;
}

Output:

1234567810111213