SpiceInt ordi_c ( SpiceInt item,
SpiceCell * set )
The function returns the ordinal position of any given item in an
integer set. If the item does not appear in the set, the function
returns -1.
SETS
SEARCH
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 an integer to be located within a set.
set is an integer CSPICE set that is to be searched for the
occurrence of item.
set must be declared as an integer 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.
1) If the input set argument is a SpiceCell of type other than
integer, 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.
None.
A natural ordering can be imposed upon 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 4
1 is 0
2 is 1
9 is 5
7 is 3
4 is 2
10 is 6
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
SPICEINT_CELL ( set, MAXSIZ );
SpiceInt inputs [MAXSIZ] =
{
8, 1, 2, 9, 7, 4, 10
};
SpiceInt expected [MAXSIZ] =
{
4, 0, 1, 5, 3, 2, 6
};
SpiceInt i;
SpiceInt iElt;
/.
Create the set.
./
for ( i = 0; i < MAXSIZ; i++ )
{
insrti_c ( inputs[i], &set );
}
/.
Examine the ordinal positions of the set's elements.
Extract each element and verify that ordi_c gives the
index at which the element is located.
./
for ( i = 0; i < card_c(&set); i++ )
{
iElt = inputs[i];
if ( ordi_c(iElt, &set) != expected[i] )
{
setmsg_c ( "Position of # was expected to be # "
"but was actually #." );
errint_c ( "#", iElt );
errint_c ( "#", expected[i] );
errint_c ( "#", ordi_c(iElt,&set) );
sigerr_c ( "INVALID LOCATION" );
}
}
return ( 0 );
}
None.
None.
N.J. Bachman (JPL)
C.A. Curzon (JPL)
H.A. Neilan (JPL)
W.L. Taber (JPL)
I.M. Underwood (JPL)
-CSPICE Version 1.0.0, 07-AUG-2002 (NJB) (CAC) (HAN) (WLT) (IMU)
the ordinal position of an element in a set
Link to routine ordi_c source file ordi_c.c
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