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elemi_c

 Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input Detailed_Output Parameters Exceptions Files Particulars Examples Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

```   elemi_c ( Element of an integer set )

SpiceBoolean elemi_c ( SpiceInt        item,
SpiceCell     * a    )

```

#### Abstract

```   Determine whether an item is an element of an integer set.
```

```   SETS
```

#### Keywords

```   CELLS
SETS

```

#### Brief_I/O

```   VARIABLE  I/O  DESCRIPTION
--------  ---  --------------------------------------------------
item       I   Item to be tested.
a          I   Set to be tested.

The function returns SPICETRUE if `item' is an element of `a'.
```

#### Detailed_Input

```   item        is an item which may or may not be an element of
the input set.

a           is a SPICE set.

`a' must be declared as an integer SpiceCell.

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

SPICEINT_CELL           ( a, ASZ );

where ASZ is the maximum capacity of `a'.
```

#### Detailed_Output

```   The function returns SPICETRUE if `item' is a member of the set `a',
and returns SPICEFALSE otherwise.
```

#### Parameters

```   None.
```

#### Exceptions

```   1)  If the `a' cell argument has a type other than SpiceInt, the
error SPICE(TYPEMISMATCH) is signaled. The function returns
the value SPICEFALSE.

2)  If the `a' cell argument does not qualify as a SPICE set, the
error SPICE(NOTASET) is signaled. SPICE sets have their data
elements stored in increasing order and contain no duplicate
elements. The function returns the value SPICEFALSE.
```

#### Files

```   None.
```

#### Particulars

```   This routine uses a binary search to check for the presence in the set
of the specified item.
```

#### 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) Check if the elements of a list of integers belong to a given
integer set.

Example code begins here.

/.
Program elemi_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"

int main( )
{

/.
Local constants.
./
#define LISTSZ       6
#define SETDIM       8

/.
Local variables.
./
SPICEINT_CELL      ( a     , SETDIM );
SpiceInt             i;

/.
Set the values of the set and the list of integers.
./
SpiceInt             values [SETDIM] = {
-1, 0, 1, 1, 3, 5, 0, -3 };

SpiceInt             items  [LISTSZ] = { 6, -1, 0, 2, 3, -2 };

/.
Add the values to the integer set using appndi_c. The
results of these calls results in a cell which does not
qualify as a set.
./
for ( i = 0; i < SETDIM; i++ )
{
appndi_c ( values[i], &a );
}

/.
Initialize the set by validating the cell: remove duplicates
and sort the elements in increasing order.
./
valid_c ( SETDIM, SETDIM, &a );

/.
Check if the items in the list belong to the set.
./
for ( i = 0; i < LISTSZ; i++ )
{
if ( elemi_c ( items[i], &a ) )
{
printf( "Item %4d is in the set.\n", items[i] );
}
else
{
printf( "Item %4d is NOT in the set.\n", items[i] );
}
}

return ( 0 );
}

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

Item    6 is NOT in the set.
Item   -1 is in the set.
Item    0 is in the set.
Item    2 is NOT in the set.
Item    3 is in the set.
Item   -2 is NOT in the set.
```

#### Restrictions

```   None.
```

#### Literature_References

```   None.
```

#### Author_and_Institution

```   N.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 1.1.0, 24-AUG-2021 (JDR)

Changed the argument name "set" to "a" for consistency with other
routines.

```   element of an integer set
`Fri Dec 31 18:41:06 2021`