to

Algorithms for Image Processing and Computer Vision Source Code

@c ----------------------------------------------------------------------
@node tolower, ctype
@heading @code{tolower}
@subheading Syntax

@example
#include <ctype.h>

int tolower(int c);
@end example

@subheading Description

This function returns @var{c}, converting it to lower case if it is
upper case.  @xref{toupper}

@subheading Return Value

The upper case letter.

@subheading Example

@example
for (i=0; buf[i]; i++)
  buf[i] = tolower(buf[i]);
@end example

@c ----------------------------------------------------------------------
@node toupper, ctype
@heading @code{toupper}
@subheading Syntax

@example
#include <ctype.h>

int toupper(int c);
@end example

@subheading Description

This function returns @var{c}, converting it to upper case if it is
lower case. @xref{tolower}

@subheading Return Value

The upper case letter.

@subheading Example

@example
for (i=0; buf[i]; i++)
  buf[i] = toupper(buf[i]);
@end example