Solution for question asked in reddit /r/c_programming

2d_pointers_and_others.c

/// for https://www.reddit.com/r/C_Programming/comments/b3wnhv/need_help_with_creating_pointers_of_a_2d_array_of/?st=JTJ6V0A6&sh=4926d7ec

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main (int argc, char** argv)
{
  // 1. Static fixed-size array
  char ss[3][4][255];

  for (int i=0; i<3; ++i)
  {
    for (int j=0; j<4; ++j)
    {
      snprintf(ss[i][j], 255, "-%d-%d-", i, j);
      printf("%s ", ss[i][j]);
    }
    printf("\n");
  }

  printf("\n\n");
  
  // 2. 2d array
  char* arrstrs[3][4];
  for (int i=0; i<3; ++i)
  {
    for (int j=0; j<4; ++j)
    {
      arrstrs[i][j] = calloc(1, sizeof(char) * 6);
      snprintf(arrstrs[i][j], 6, "-%d-%d-", i, j);
      printf("%s ", arrstrs[i][j]);
    }
    printf("\n");
  }

  // do something with string inside 2d array of string here ...

  // free strings
  for (int i=0; i<3; ++i)
  {
    for (int j=0; j<4; ++j)
    {
      free(arrstrs[i][j]);
      arrstrs[i][j] = NULL;
    }
  }

  printf("\n\n");

  // 3. single pointer represents 2d array of string as 1d
  char* ss2;
  ss2 = calloc(1, sizeof(char) * 3 * 4 * 255);
  for (int row=0; row<3; ++row)
  {
    for (int col=0; col<4; ++col)
    {
      snprintf((ss2 + row*4*255) + col*255, 255, "-%d-%d-", row, col);
      printf("%s ", (ss2 + row*4*255) + col*255);
    }
    printf("\n");
  }

  // free strings
  free(ss2);
  ss2 = NULL;

  printf("\n\n");

  // 4. double pointers for 2d array of string
  char** ss3;
  ss3 = calloc(1, sizeof(char*) * 3);
  for (int row=0; row<3; ++row)
  {
    *(ss3 + row) = calloc(1, sizeof(char) * 4 * 255);

    // set strings
    snprintf((*(ss3 + row) + 0), 255, "-%d-%d-", row, 0);
    snprintf((*(ss3 + row) + 1*255), 255, "-%d-%d-", row, 1);
    snprintf((*(ss3 + row) + 2*255), 255, "-%d-%d-", row, 2);
    snprintf((*(ss3 + row) + 3*255), 255, "-%d-%d-", row, 3);

    printf("%s %s %s %s\n",
        *(ss3 + row),
        *(ss3 + row) + 1*255,
        *(ss3 + row) + 2*255,
        *(ss3 + row) + 3*255);
  }

  // free strings
  for (int row=0; row<3; ++row)
  {
    free(ss3[row]);
    ss3[row] = NULL;
  }
  free(ss3);
  ss3 = NULL;

  return 0;
}