Return value don't return

Question

I wrote a word_pattern function as below.

I didn't get a return value, what's wrong with the code?

Below is the codewars training.( https://www.codewars.com/kata/5f3142b3a28d9b002ef58f5e/train/c )

#include <stdlib.h>
#include <string.h> //strlen
#include <ctype.h> //islower

char *word_pattern(const char *word) {
  int i, j;
  int size = strlen(word) ;
  char *ans = (char*)malloc(sizeof(char) * (size * 2 ));

  char *base = ans;

  if (ans == NULL)
  {
    return NULL;
  }

  for (i = 0; i < size; i++)
  {
    if (i == 0)
    {
      *ans++ = (char)i;
      *ans++ = '.';
      /*break;*/ continue;
    }

    for (j = 0; j < i; j++)
    {
      if ( islower(word[i]) == islower(word[j]) )
      {
        *ans++ = (char)j;
        *ans++ = '.';
        break;
      }
    }
    
    if(j == i)
    {
      *ans++ = (char)i;
      *ans++ = '.';
    }
  }

  *--ans = '\0';
  return base;
}

Answer 1

I didn't get a return value, what's wrong with the code?

Below code sets ans[0] to 0, the null character .

if (i == 0) {
  *ans++ = (char)i;

Printing the return pointer as a string prints nothing as the string ends immediately.