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From: weimer@ssd.kodak.com (Gary Weimer)
Newsgroups: comp.lang.c
Subject: Re: Trouble with curses
Message-ID: <1990Nov7.194154.6071@ssd.kodak.com>
Date: 7 Nov 90 19:41:54 GMT
References: <173826@<1990Oct27> <20900012@inmet>
Sender: news@ssd.kodak.com
Organization: Eastman Kodak
Lines: 16

In article <20900012@inmet> draper@inmet.inmet.com writes:
>
>  switch(tolower(getch())) {
>  /* I would watch out on the above line of code. tolower is a */
>  /* macro that might have undesriable effects should the user */
>  /* enter a character that is already in lower case. A good   */
>  /* thing to do would be check if the char was an upper case  */
>  /* using "isupper" before calling "tolower".                 */

ANSI complient definition of tolower() does call islower() before
making the conversion. In this case, the code "expands" to:

    switch(islower(getch()) ? tolower(getch()) : (getch())) {

Note that you are now always making two calls to getch() (as someone
has already pointed out is a possibility).