Re: convert 1D array to 3D array

From:
"Ondra Holub" <ondra.holub@post.cz>
Newsgroups:
comp.lang.c++.moderated
Date:
10 Dec 2006 18:19:22 -0500
Message-ID:
<1165785953.078649.4610@j72g2000cwa.googlegroups.com>
andy napsal:

Dear Readers:

I tried to convert 1D array to 3D array but failed. Is there any
possible way to do that?
If not, what is the simpler way to map 1-dimension array to
multi-dimension array.

Thanks in advanced.

int main(void)
{
    int m1[3*4*5];
    int m3[3][4][5];

    m1[1*4*5 + 2*5 +3] = m3[1][2][3] = 10;

    int (*m2)[4][5] = (int *[4][5])m1; ======> line 18
    printf(" m1[1][2][3] = %d\n", m2[1][2][3]);
}

multiarray.cpp:18: error: ISO C++ forbids casting to an array type
`int*[4][5]'

Cheers,
Andy


Hi. See function 'Set' for conversion:

#include <iostream>
#include <iomanip>

static const size_t A = 5;
static const size_t B = 4;
static const size_t C = 3;

static int m1[A * B * C];
static int m3[A][B][C];

void Set(size_t x, size_t y, size_t z, int value)
{
    m1[x + A * (y + B * z)] = m3[x][y][z] = value;
}

int main(void)
{
    int value = 0;

    // Set sequentialy all values
    for (size_t k = 0; k < C; ++k)
        for (size_t j = 0; j < B; ++j)
            for (size_t i = 0; i < A; ++i)
                 Set(i, j, k, ++value);

    // Dump 3d array
    for (size_t k = 0; k < C; ++k)
    {
        for (size_t j = 0; j < B; ++j)
        {
            for (size_t i = 0; i < A; ++i)
            {
                std::cout << std::setw(5) << m3[i][j][k];
            }
            std::cout << "\n";
        }
        std::cout << "\n";
    }

    // Dump 1d array
    for (int i = 0; i < A * B * C; ++i)
    {
        std::cout << std::setw(5) << m1[i];
    }

    std::cout << "\n\n";
}

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