Thread: Question(s) concerning case insensitive string comparisons

First a compiler question...then the REAL question.

Given this strucutre...

Code:

  typedef struct Key  KEY;
  typedef struct Key* KEYS;

struct Key 
  {
      char *sender;
      char *addressee;
      char *regarding;
      DATE date;
      int id;
      char *fname;
      KEYS next;
  };

why would my compiler complan that there is a signed/unsigned mismatch with this for loop statement?

Code:

KEYS search(KEYS k, KEY ki )
{
....some code....

    for(i=0;i<=strlen(ki.sender); i++)
          temp.sender[i]=tolower(ki.sender[i]);


...some more case conversion
}

what's weird is that the compiler does not complian if I do it like this.

Code:

len=strlen(ki.sender)
for(i=0;i<=len; i++)
      temp.sender[i]=tolower(ki.sender[i]);

utlimately, what I am trying to do is prepare two strings for a non-case sensitive comparison. So that "BARBARA" would match "Barbara".

Is there an easier (or more clever) way to do this operation on a string beside the way I am trying to do it in the for loop up above? I hate using the temp.


Thanks,
Mike