Procedure

   void shellc_c ( SpiceInt     ndim,
                   SpiceInt     lenvals,
                   void       * array   ) 

Abstract

 
   Sort an array of character strings according to the ASCII 
   collating sequence using the Shell Sort algorithm. 
 

Required_Reading

 
   None. 
 

Keywords

 
    ARRAY,  SORT 
 

Brief_I/O

 
   VARIABLE  I/O  DESCRIPTION 
   --------  ---  -------------------------------------------------- 
   ndim       I   Dimension of the array. 
   lenvals    I   String length.
   array     I/O  The array. 
 

Detailed_Input

 
   ndim        is the number of elements in the array to be sorted. 

   lenvals     is the declared length of the strings in the input
               string array, including null terminators.  The input   
               array should be declared with dimension 

                  [ndim][lenvals]

   array       on input, is the array to be sorted. 
 

Detailed_Output

 
   array       on output, contains the same elements, sorted 
               according to the ASCII collating sequence. 
               The actual sorting is done in place in array. 
 

Parameters

 
   None. 
 

Exceptions

 
   1) If ndim < 2, this routine does not modify the array.

   2) If the input string array pointer is null, the error
      SPICE(NULLPOINTER) will be signaled.
 
   3) If the input array string length is less than 2, the error
      SPICE(STRINGTOOSHORT) will be signaled.

Files

 
    None. 

Particulars

 
   The Shell Sort Algorithm is well known. 
 

Examples

 
   Let array contain the following elements: 

      "FEYNMAN" 
      "NEWTON" 
      "EINSTEIN" 
      "GALILEO" 
      "EUCLID" 
      "Galileo" 

   Then after a call to shellc_c, the array would be ordered as 
   follows: 

      "EINSTEIN" 
      "EUCLID" 
      "FEYNMAN" 
      "GALILEO" 
      "Galileo" 
      "NEWTON" 

Restrictions

 
   1)  The input array is assumed to be sorted in increasing order. If 
       this condition is not met, the results of bsrchc_c are unpredictable.

   2)  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_References

 
   None. 
 

Author_and_Institution

 
   N.J. Bachman    (JPL)
   I.M. Underwood  (JPL) 
 

Version

 
  -CSPICE Version 1.0.0, 18-JUL-2002 (NJB) (IMU)

Index_Entries

 
   shell sort a character array 
 

Link to routine shellc_c source file shellc_c.c