toupper(); tolower(); ?

**dune911** · 01-07-2003

hi there
are there functions like toupper(); and tolower();
which i know from php that i can use in C ?

**Vber** · 01-07-2003

ctype.h

Code:

#include <ctype.h>

Good luck

**dune911** · 01-07-2003

uh

thanks!

**ronin** · 01-07-2003

Should you ever be caught w/o ctype.h

Code:

#include <stdio.h>

int main(void)
{
   char aString[] = "THiS # Is && A && CRazY # strING\n";
   int i, letter;
   
   printf("%s", aString); 
         
   for(i=0; aString[i] != '\0'; i++)
   {
      letter = aString[i];
      /* to upper */
      if(letter >= 97 && letter <= 122)
      	aString[i] = letter - 32;
   }
   
   printf("toupper: %s", aString);
   
   for(i=0; aString[i] != '\0'; i++)
   {
      letter = aString[i];
      /* to lower */
      if(letter >= 65 && letter <= 90)
        aString[i] = letter + 32;
   }
   
   printf("tolower: %s", aString);

   return 0;
}

**dune911** · 01-07-2003

nice

thank you

**quzah** · 01-07-2003

Originally posted by ronin
Should you ever be caught w/o ctype.h

Code:

if(letter >= 97 && letter <= 122) aString[i] = letter - 32; if(letter >= 65 && letter <= 90) aString[i] = letter + 32; }

Non portable. But then, why would you be without ctype.h in the first place?

Quzah.

**ronin** · 01-07-2003

I enjoy thinking of ways to replicate the functions supported by the compiler, and I deal primarily with Dos instead of other platforms such as Unix, Linux, Win32 etc, so those methods have worked.

It may be a lot of extra work, but it helps me to understand what's going on, and isn't that the purpose of learning in general?.... I've never taken a C course, but I've had one semester of intro C++

You care to elaborate on the non portability? Is it the numbering systems?

What about replacing int with a char and using 'a' && 'z' ?

**Dave_Sinkula** · 01-07-2003

>You care to elaborate on the non portability?
C does not assume ASCII; in EBCDIC, letters of the alphabet are not contiguous.

>What about replacing int with a char and using 'a' && 'z' ?
Better, but no -- still not portable.

**Hammer** · 01-07-2003

>>You care to elaborate on the non portability?
You need to look at the different between the ASCII and EBCDIC charts.

A simple observation is that in the ASCII chart, the uppercase A-Z are 65 to 90, and the lower case a-z are 97 to 122.

Whereas, the EBCDIC chart has these in different places completely. Take a look at this table and you'll see that a-z are not even in one contiguous block, so addition/subtraction on them won't work the same as ASCII.

[edit]Doh!

**ronin** · 01-07-2003

Hmm... I never thought about that.

A new topic to hunt down and conquer.

Thanks Dave... nice source, and as always thanks Hammer.

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