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brckti_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

brckti_c ( Bracket an integer value within an interval )

SpiceInt brckti_c ( SpiceInt  number,
SpiceInt  end1,
SpiceInt  end2   )

#### Abstract

Bracket an integer number. That is, given a number and an
acceptable interval, make sure that the number is contained in the
interval. (If the number is already in the interval, leave it
alone. If not, set it to the nearest endpoint of the interval.)

None.

INTERVALS
NUMBERS
UTILITY

#### Brief_I/O

VARIABLE  I/O  DESCRIPTION
--------  ---  --------------------------------------------------
number     I   Number to be bracketed.
end1       I   One of the bracketing endpoints for `number'.
end2       I   The other bracketing endpoint for `number'.

The function returns the bracketed number.

#### Detailed_Input

number      is the number to be bracketed. That is, the
value of `number' is constrained to lie in the
interval bounded by `end1' and `end2'.

end1,
end2        are the lower and upper bounds for `number'. The
order is not important.

#### Detailed_Output

The function returns the bracketed number. That is `number', if it
was already in the interval provided. Otherwise the returned
value is the nearest bound of the interval.

None.

Error free.

None.

#### Particulars

This routine provides a shorthand notation for code fragments
like the following:

if ( end1 < end2 )
{
if ( number < end1 )
{
number = end1;
}
else if ( number > end2 )
{
number = end2;
}
}
else
{
if ( number < end2 )
{
number = end2;
}
else if ( number > end1 )
{
number = end1;
}
}

which occur frequently during the processing of program inputs.

#### Examples

The numerical results shown for these examples 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 illustrates the operation of
brckti_c.

Example code begins here.

/.
Program brckti_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"

int main( )
{

/.
Local parameters.
./
#define LISTSZ       4

/.
Local variables.
./
SpiceInt             i;

/.
Set the values for the example.
./
SpiceInt             end1   [LISTSZ] = {  1,  1,  10, -10 };
SpiceInt             end2   [LISTSZ] = { 10, 10, -10,  -1 };
SpiceInt             number [LISTSZ] = { -1, 29,   3,   3 };

printf( "Number  End1  End2  Bracketed\n" );
printf( "------  ----  ----  ---------\n" );

for ( i = 0; i < LISTSZ; i++ )
{

printf( "%6d %5d %5d %10d\n",
number[i], end1[i], end2[i],
brckti_c ( number[i], end1[i], end2[i] ) );

}

return ( 0 );
}

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

Number  End1  End2  Bracketed
------  ----  ----  ---------
-1     1    10          1
29     1    10         10
3    10   -10          3
3   -10    -1         -1

2) The following code example illustrates a typical use for
brckti_c: force an identifier to be within a range. Note that
this code assumes that the user provided value is a valid
integer number.

Example code begins here.

/.
Program brckti_ex2
./
#include <stdio.h>
#include "SpiceUsr.h"

int main( )
{

/.
Local parameters.
./
#define KWDSZ        31

/.
Local variables.
./
SpiceChar            usrin  [KWDSZ];

SpiceInt             codein;
SpiceInt             codeok;

/.
Prompt the user for the code identifier.
./
prompt_c ( "Enter object code: ", KWDSZ, usrin );

/.
Convert the user input to integer.
./
prsint_c ( usrin, &codein );

/.
Object code must be in the range 701-705.
./
codeok = brckti_c ( codein, 701, 705 );

/.
Display confirmation message.
./
if ( codein != codeok )
{
printf( "Provided object code %3d is out of range (701-705).\n",
(int)codein );
}
else
{
printf( "Provided object code %3d is in range (701-705).\n",
(int)codein );
}

return ( 0 );
}

When this program was executed on a Mac/Intel/cc/64-bit
platform, using "710" as user provided input, the output was:

Enter object code: 710
Provided object code 710 is out of range (701-705).

None.

None.

#### Author_and_Institution

N.J. Bachman        (JPL)
J. Diaz del Rio     (ODC Space)
B.V. Semenov        (JPL)
W.L. Taber          (JPL)
I.M. Underwood      (JPL)
E.D. Wright         (JPL)

#### Version

-CSPICE Version 1.1.0, 10-AUG-2021 (JDR) (BVS)

BUG FIX: corrected to make the order of endpoints not important
as stated in the description.

code examples based on existing fragments.

Updated code fragment in -Particulars to show that the
order of endpoints is not important.

-CSPICE Version 1.0.1, 11-NOV-2006 (EDW)

Added "None." text to -Keywords section, required for
API doc script (cspicehtml.pl) integrity checks.

-CSPICE Version 1.0.0, 16-AUG-1999 (NJB) (WLT) (IMU)

#### Index_Entries

bracket an integer value within an interval
Fri Dec 31 18:41:02 2021