如何在 function 参数中传递指针的多维 arrays 并对其进行操作？

Question

So I have an array of pointers that this defined like so:

    sf::Sprite * game[3][3] = {{nullptr, nullptr, nullptr},
                       {nullptr, nullptr, nullptr},
                       {nullptr, nullptr, nullptr}};

It was working perfectly until I wanted to pass it into a function argument. I tried multiple parameters and arguments and this works:

#include <iostream>

void printTwoDPointersArr(int * myArray[][3])
{
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            std::cout << *myArray[i][j];
}

int main()
{
    int myRealArray[3][3] = {{0, 1, 2}, {3, 4, 5}, {0, 1, 2}};
    int * myPointingArray[3][3];
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            myPointingArray[i][j] = &myRealArray[i][j];
    printTwoDPointersArr(&myPointingArray[0]);
}

But then, if I want to create an second array that refers to the same array than myPointingArray, i just can't. I don't want a copy of the array, because copies are not updated when the original one is changed: I need a reference. I tried this:

#include <iostream>

void printTwoDPointersArr(int * myArray[][3])
{
    int * mySecondArray = &myArray[0];
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            std::cout << *mySecondArray[i][j];
}

int main()
{
    int myRealArray[3][3] = {{0, 1, 2}, {3, 4, 5}, {0, 1, 2}};
    int * myPointingArray[3][3];
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            myPointingArray[i][j] = &myRealArray[i][j];
    printTwoDPointersArr(&myPointingArray[0]);
}

But I get the following error:

/path/main.cpp:5: error: cannot convert ‘int* (*)[3]’ to ‘int*’ in initialization
/path/main.cpp:5:27: error: cannot convert ‘int* (*)[3]’ to ‘int*’ in initialization
    5 |     int * mySecondArray = &myArray[0];
      |                           ^~~~~~~~~~~
      |                           |
      |                           int* (*)[3]

So, the question is: is there an easy way to manipulate multidimensional array of pointers, and to create a reference to them?

I am new to stack overflow, please tell me if I'm doing wrong. Thank you !

Answer 1

Why don't you just assemble the array of pointers mySecondArray[3][3] the same way you did in the main() with myPointingArray ?

They will both point to the same underlying object.

#include <iostream>

void printTwoDPointersArr(int * myArray[][3])
{
    int * mySecondArray[3][3];
    // now just assemble the array of pointers as done in main()
    for (int i = 0; i < 3; i++)      
        for (int j = 0; j < 3; j++)
            mySecondArray[i][j] = myArray[i][j];
            
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            std::cout << *mySecondArray[i][j];
}

int main()
{
    int myRealArray[3][3] = {{0, 1, 2}, {3, 4, 5}, {0, 1, 2}};
    int * myPointingArray[3][3];
    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++)
            myPointingArray[i][j] = &myRealArray[i][j];
    printTwoDPointersArr(&myPointingArray[0]);
}