#include <stdio.h>
#include <malloc.h>

int** malloc2d(int row, int col)
{
    int** ret = NULL;

    if( (row > 0) && (col > 0) )
    {
        int* p = NULL;

        ret = (int**)malloc(row * sizeof(int*));
        p = (int*)malloc(row * col * sizeof(int));

        if
 
( (ret != NULL) && (p != NULL) )
        {
            int i = 0;

            for(i=0; i<row; i++)
            {
                ret[i] = p + i * col;
            }
        }
        else
        {
            free(ret);
            free(p);

            ret = NULL;
        }

    }

    return
 
 ret;
}

void free2d(int** p)
{
    if( *p != NULL )
    {
        free(*p);
    }

    free(p);
}

int main()
{
    int** a = malloc2d(3, 3);
    int i = 0;
    int j = 0;

    for(i=0; i<3; i++)
    {
        for(j=0; j<3; j++)
        {
            printf("%d, ", a[i][j]);
        }

        printf
 
("\n");
    }

    free2d(a);

    return 0;
}