返回指向多维数组的指针

Question

Let's say I'm creating a multidimensional array as follows.

const int array_temp[3][2][1] = {
    [0] = {{0}, {1}},
    [1] = {{2}, {3}},
    [2] = {{4}, {5}},
};

This array represents 3 tables of 2 entries in each table.

How would I return a pointer to the start of one of the 3 tables? Would it be as follows?

return (void *)&array_temp[idx][0][0];

Answer 1

In a 3D case, derefernce the pointer name once leads us to the Zeroth row. This means that adding idx to the dereferenced name would lead us to the idx'th row(Where idx>=0)

return ((*array_temp)+idx);

But be sure that you don't declare the array inside the function. As its duration is till the function ends

Answer 2

Try return array_temp[idx] . the return array_temp[idx][0][0] will return a specific content not the (container) array itself.

Answer 3

This example is self explanatory I think

#include <stdio.h> 

char arr[4][5][6];



int main(int argc, char *argv[]) {

    printf("%d\n\r", sizeof *(arr));
    printf("%d\n\r", sizeof *(arr[0]));
    printf("%d\n\r", sizeof *(arr[0][0]));
    printf("%d\n\r", sizeof *(&arr));
    printf("%d\n\r", sizeof *(&arr[0]));
    printf("%d\n\r", sizeof *(&arr[0][0]));

}

And the result:

30
6
1
120
30
6

Nothing to add I think