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The function returns the ordinal position of any given item in a character set. If the item does not appear in the set, the function returns -1.
SETS
VARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- item I An item to locate within a set. set I A set to search for a given item. The function returns the ordinal position of item within the set.
item is a character string to be located within a set.
Trailing blanks are not significant in the comparison.
set is an integer CSPICE set that is to be searched for the
occurrence of item. Trailing blanks are not significant
in the comparison.
set must be declared as a character SpiceCell.
The function returns the ordinal position of item within set. Ordinal positions range from 0 to N-1, where N is the cardinality of the set. If item is not an element of set, the function returns -1.
None.
A natural ordering can be imposed upon the the elements of any
CSPICE set, be it integer, character or double precision. For
character strings the ASCII collating sequence serves as the
ordering relation, for double precision and integer variables
the arithmetic ordering is used.
Given any element of a set, its location within this ordered
sequence of elements is called its ordinal position within
the set.
In common mathematical usage, ordinal positions of elements
in a set of cardinality N range from 1 to N. In C programs,
it is much more convenient to use the range 0 to N-1; this is
the convention used in CSPICE.
For illustrative purposes suppose that set represents the set
{ "8", "1", "2", "9", "7", "4", "10" }
The ordinal position of:
"8" is 5
"1" is 0
"2" is 2
"9" is 6
"7" is 4
"4" is 3
"10" is 1
1) Obtain the ordinal positions shown in the table of the Particulars
section above.
#include "SpiceUsr.h"
int main()
{
/.
Declare an integer set and populate it with the elements
shown above.
./
#define MAXSIZ 7
#define ITMLEN 10
SPICECHAR_CELL ( set, MAXSIZ, ITMLEN );
SpiceChar * cElt;
SpiceChar inputs [MAXSIZ][ITMLEN] =
{
"8", "1", "2", "9", "7", "4", "10"
};
SpiceInt expected [MAXSIZ] =
{
5, 0, 2, 6, 4, 3, 1
};
SpiceInt i;
/.
Create the set.
./
for ( i = 0; i < MAXSIZ; i++ )
{
insrtc_c ( inputs[i], &set );
}
/.
Examine the ordinal positions of the set's elements.
Extract each element and verify that ordc_c gives the
index at which the element is located.
./
for ( i = 0; i < card_c(&set); i++ )
{
cElt = inputs[i];
if ( ordc_c(cElt, &set) != expected[i] )
{
setmsg_c ( "Position of # was expected to be # "
"but was actually #." );
errch_c ( "#", cElt );
errint_c ( "#", expected[i] );
errint_c ( "#", ordc_c(cElt,&set) );
sigerr_c ( "INVALID LOCATION" );
}
}
return ( 0 );
}
1) String comparisons performed by this routine are Fortran-style:
trailing blanks in the input array or key value are ignored.
This gives consistent behavior with CSPICE code generated by
the f2c translator, as well as with the Fortran SPICE Toolkit.
Note that this behavior is not identical to that of the ANSI
C library functions strcmp and strncmp.
1) If the input set argument is a SpiceCell of type other than
character, the error SPICE(TYPEMISMATCH) is signaled.
2) If the input set argument does not qualify as a CSPICE set,
the error SPICE(NOTASET) will be signaled. CSPICE sets have
their data elements sorted in increasing order and contain
no duplicate data elements.
3) If the input string pointer is null, the error SPICE(NULLPOINTER)
is signaled.
None.
N.J. Bachman (JPL) C.A. Curzon (JPL) H.A. Neilan (JPL) W.L. Taber (JPL) I.M. Underwood (JPL)
None.
-CSPICE Version 1.0.0, 21-AUG-2002 (NJB) (CAC) (HAN) (WLT) (IMU)
the ordinal position of an element in a set