Procedure

   wncard_c ( Cardinality of a double precision window ) 

   SpiceInt wncard_c ( SpiceCell  * window )

Abstract

   Return the cardinality (number of intervals) of a double
   precision window.

Required_Reading

   WINDOWS

Keywords

   WINDOWS

Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   window     I   Input window

   The function returns the window cardinality of the window.

Detailed_Input

   window      is a window containing zero or more intervals.

               `window' must be declared as a double precision SpiceCell.

               CSPICE provides the following macro, which declares and
               initializes the cell

                  SPICEDOUBLE_CELL        ( window, WINDOWSZ );

               where WINDOWSZ is the maximum capacity of `window'.

Detailed_Output

   The function returns the cardinality of (number of intervals in)
   the input window.

Parameters

   None.

Exceptions

   1)  If the number of elements in `window' is not even, the error
       SPICE(INVALIDSIZE) is signaled by a routine in the call tree
       of this routine.

   2)  If the `window' cell argument has a type other than
       SpiceDouble, the error SPICE(TYPEMISMATCH) is signaled. The
       function returns the value 0.

Files

   None.

Particulars

   This function returns the value of card_c(window)/2.

Examples

   The 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) The following code example demonstrates how to insert an
      interval into an existing double precision SPICE window, and
      how to loop over all its intervals to extract their left and
      right points.


      Example code begins here.


      /.
         Program wncard_ex1
      ./
      #include <stdio.h>
      #include "SpiceUsr.h"

      int main()
      {

         /.
         Local parameters.
         ./
         #define WNSIZE          10

         /.
         Local variables.
         ./
         SpiceDouble              left;
         SpiceDouble              right;

         SPICEDOUBLE_CELL ( window,  WNSIZE );

         SpiceInt                 i;

         /.
         Validate the window with size WNSIZE and zero elements.
         ./
         wnvald_c ( WNSIZE, 0, &window );

         /.
         Insert the intervals

            [ 1, 3 ]  [ 7, 11 ]  [ 23, 27 ]

         into `window'.
         ./
         wninsd_c (  1.0,   3.0, &window );
         wninsd_c (  7.0,  11.0, &window );
         wninsd_c ( 23.0,  27.0, &window );

         /.
         Loop over the number of intervals in `window', output
         the `left' and `right' endpoints for each interval.
         ./
         for ( i=0; i<wncard_c(&window); i++)
         {
            wnfetd_c( &window, i, &left, &right );
            printf("Interval %d [%8.3f, %8.3f]\n", i, left, right );
         }

         return ( 0 );

      }


      When this program was executed on a Mac/Intel/cc/64-bit
      platform, the output was:


      Interval 0 [   1.000,    3.000]
      Interval 1 [   7.000,   11.000]
      Interval 2 [  23.000,   27.000]

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   J. Diaz del Rio     (ODC Space)
   E.D. Wright         (JPL)

Version

   -CSPICE Version 1.0.1, 05-AUG-2021 (JDR)

       Edited the header to comply to NAIF standard. Created complete code
       example from code fragment and added example's problem statement.

       Extended description of argument "window" in -Detailed_Input to include
       type and preferred declaration method.

       Completed -Exceptions section.

   -CSPICE Version 1.0.0, 21-AUG-2007 (EDW)

Index_Entries

   cardinality of a d.p. window

Link to routine wncard_c source file wncard_c.c