[C]: How I think 3D arrays expressed in C.

/*
    int a[3];

    [1, 2, 3]
     |  |  |
     /  |  \
    50  60  70
    ----------

    int a[3][2]

    1, 2
    3, 4
    5, 6
    ----------

    int a[5];

    1, 2, 3, 4, 5 -- 1 dimensional

    int a[5][4];

    1, 2, 3, 4 }
    5, 6, 7, 8
    9, 10, 11, 12 } -- 2 dimensional
    13, 14, 15, 16
    17, 18, 19, 20 }

    ----------
    int a[5][4][2]
    3D = {
            1,  3,  5,  7,
                *[1: 1, 2], *[3: 3, 4], *[5: 5, 6], *[7: 7, 8]
            9,  11, 13, 15,
                *[9: 9, 10], *[11: 11, 12], *[13: 13, 14], *[15: 15, 16]
            17, 19, 21, 23,
                *[17: 17, 18], *[19: 19, 20], *[21: 21, 22], *[23: 23, 24]
            25, 27, 29, 31,
                *[25: 25, 26], *[27: 27, 28], *[29: 29, 30], *[31: 31, 32]
            33, 35, 37, 39,
                *[33: 33, 34], *[35: 35, 36], *[37: 37, 38], *[39: 39, 40]
    }

    (size = 40) (for 3D)
*/

#include <stdio.h>

int main()
{
    int intsize = sizeof(int);

    int a_1d[5];
    int a_2d[5][4];
    int a_3d[5][4][2];

    int size_a1d = sizeof(a_1d) / intsize;
    int size_a2d = sizeof(a_2d) / intsize;
    int size_a3d = sizeof(a_3d) / intsize;

    printf("(Dimensional sizes with sets: {5, 4, 2})\n\n1D[%d]: %lu,\n2D[%d][%d]: %lu,\n3D[%d][%d][%d]: %lu;", 5, size_a1d, 5, 4, size_a2d, 5, 4, 2, size_a3d); // matches predictions
    return 0;
}