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brcktd_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

```   brcktd_c ( Bracket a d.p. value within an interval )

SpiceDouble brcktd_c ( SpiceDouble  number,
SpiceDouble  end1,
SpiceDouble  end2   )

```

#### Abstract

```   Bracket a double precision 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.
```

#### Keywords

```   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.
```

#### Parameters

```   None.
```

#### Exceptions

```   Error free.
```

#### Files

```   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
brcktd_c.

Example code begins here.

/.
Program brcktd_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"

int main( )
{

/.
Local parameters.
./
#define LISTSZ       4

/.
Local variables.
./
SpiceInt             i;

/.
Set the values for the example.
./
SpiceDouble          end1   [LISTSZ] = {  1.0,   1.0,  10.0, -10.0 };
SpiceDouble          end2   [LISTSZ] = { 10.0,  10.0, -10.0,  -1.0 };
SpiceDouble          number [LISTSZ] = { -1.0,  29.0,  3.0,    3.0 };

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

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

printf( "%7.1f %6.1f %6.1f %10.1f\n",
number[i], end1[i], end2[i],
brcktd_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
------  -----  -----  ---------
-1.0    1.0   10.0        1.0
29.0    1.0   10.0       10.0
3.0   10.0  -10.0        3.0
3.0  -10.0   -1.0       -1.0

2) The following code example illustrates a typical use for
brcktd_c: force a start magnitude limit to be within a range.
Note that this code assumes that the user provided value
is a valid double precision number.

Example code begins here.

/.
Program brcktd_ex2
./
#include <stdio.h>
#include "SpiceUsr.h"

int main( )
{

/.
Local parameters.
./
#define KWDSZ        31

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

SpiceDouble          maglin;
SpiceDouble          maglok;

/.
Prompt the user for the star magnitude.
./
prompt_c ( "Enter star magnitude: ", KWDSZ, usrin );

/.
Convert the user input to double precision.
./
prsdp_c ( usrin, &maglin );

/.
Star magnitude must be in the range 0-10.
./
maglok = brcktd_c ( maglin, 0.0, 10.0 );

/.
Display confirmation message.
./
if ( maglin != maglok )
{
printf( "Provided star magnitude %3.1f is out of range (0-10).\n",
maglin );
}
else
{
printf( "Provided star magnitude %3.1f is in range (0-10).\n",
maglin );
}

return ( 0 );
}

When this program was executed on a Mac/Intel/cc/64-bit
platform, using "10.1" as user provided input, the output was:

Enter star magnitude: 10.1
Provided star magnitude 10.1 is out of range (0-10).
```

#### Restrictions

```   None.
```

#### Literature_References

```   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, 08-AUG-2021 (JDR) (BVS)

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

Edited the header to comply with NAIF standard. Added complete
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 a d.p. value within an interval
```
`Fri Dec 31 18:41:02 2021`