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ascpos.c
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C/C++ Source or Header
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1993-10-14
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78 lines
/*
* GT CLIPPER STANDARD HEADER
*
* File......: ascpos.c
* Author....: Andy M Leighton
* BBS.......: The Dark Knight Returns
* Net/Node..: 050/069
* User Name.: Andy Leighton
* Date......: 23/05/93
* Revision..: 1.00
*
* This is an original work by Andy Leighton and is placed in the
* public domain.
*
* Modification history:
* ---------------------
*
* $Log$
*
*/
/*
* $DOC$
* $FUNCNAME$
* GT_ASCPOS()
* $CATEGORY$
* String
* $ONELINER$
* Return the ascii value of a specified character in a string
* $SYNTAX$
* GT_Ascpos(<cStr>, <nPos>) --> nAscVal
* $ARGUMENTS$
* <cStr> - The string
* <nPos> - The position in <cStr>
* $RETURNS$
* nAscVal - The ascii value of substr(<cStr>, <nPos>, 1)
* $DESCRIPTION$
* Return the ascii value of a specified character in a string
* Equivalent (but much faster) to
* asc(substr(cStr, nPos, 1)
*
* NOTE:
* invalid parameters will return -1
* nPos > len(cStr) will return -2
*
* This last behaviour is different to the Funcky function of the
* same name. I changed the behaviour because some of the strings
* I process contain embedded NULs.
* $EXAMPLES$
* ? gt_ascpos("the cat sat on the mat", 3)
* // prints e
* $END$
*/
#include "extend.h"
CLIPPER
gt_ascpos()
{
char *s;
int p;
if (ISCHAR(1) && ISNUM(2)) {
s = _parc(1);
p = _parni(2);
p--; // decrement p to adjust for c strings
// starting at position 0
if (p > _parclen(1)) // oh oh p > length of passed string
_retni(-2); // error -2
else
_retni((int) s[p]); // return ascii code of appropriate
// character in string
} else {
_retni(-1); // parameter mismatch - error -1
}
}