atof function question

I thought if atof was used on a string containing spaces it would not work. I have inserted spaces before the string and after. The atof still converts the string to a double. Is that everyone elses understanding as well? Using the code below I always get 23.345 when using all 3 strcpy's below. Confused.....

Code:

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strcpy(hardness, "23.345 ");
strcpy(hardness, " 23.345");
strcpy(hardness, "23.345");

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Code:

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  char hardness[256];
  double hardness2 =0;
 
  strcpy(hardness, "23.345 ");

 
  hardness2 = atof(hardness);

  printf("%1f\n", hardness2);

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Yes, that's correct.
Leading spaces are skipped.

Will it cause any problems if the space is after the string like below?

"23.345 "

Leading and/or trailing spaces don't cause problems.

atof is deprecated, and is equivalent to strtod(str, (char **)NULL);

Here's the info on strtod and how it parses the string.
http://www.hmug.org/man/3/strtod.php