ordc_c |

Table of contents## Procedureordc_c ( The ordinal position of an element in a set ) SpiceInt ordc_c ( ConstSpiceChar * item, SpiceCell * set ) ## AbstractReturn the ordinal position of a given item in a set. If the item does not appear in the set, return -1. ## Required_ReadingSETS ## KeywordsSEARCH SETS ## Brief_I/OVARIABLE 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. ## Detailed_Inputitem is a string to be located within a character set. Trailing blanks are not significant in the comparison. set is a properly validated SPICE 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. CSPICE provides the following macro, which declares and initializes the cell SPICECHAR_CELL ( set, SETSZ, SETMLEN ); where SETSZ is the maximum capacity of `set' and SETMLEN is the maximum length of any member in the character cell. ## Detailed_OutputThe 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. ## ParametersNone. ## Exceptions1) If the input set has invalid cardinality, an error is signaled by a routine in the call tree of this routine. ## FilesNone. ## ParticularsA natural ordering can be imposed upon the elements of any SPICE 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 ## ExamplesThe numerical results shown for this example may differ across platforms. The results depend on the SPICE kernels used as input, the compiler and supporting libraries, and the machine specific arithmetic implementation. 1) Obtain the ordinal positions shown in the table of the -Particulars section above. Example code begins here. /. Program ordc_ex1 ./ #include <stdio.h> #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 ## Restrictions1) 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. ## Literature_ReferencesNone. ## Author_and_InstitutionN.J. Bachman (JPL) C.A. Curzon (JPL) J. Diaz del Rio (ODC Space) H.A. Neilan (JPL) W.L. Taber (JPL) I.M. Underwood (JPL) ## Version-CSPICE Version 1.0.1, 01-NOV-2021 (JDR) Edited the header to comply with NAIF standard. Updated the example code to generate outputs and provided example's solution. Extended description of argument "set" in -Detailed_input to include type and preferred declaration method. Added entries #1 and #2 to -Exceptions section. -CSPICE Version 1.0.0, 21-AUG-2002 (NJB) (CAC) (HAN) (WLT) (IMU) ## Index_Entriesthe ordinal position of an element in a set |

Fri Dec 31 18:41:10 2021