Shell Programming and Scripting

echo "1.1+1" | bc

dc -e '1.1 1+p'

# ------------------------------------------------------------------------------
# f_Round                                                      rounding numbers
# ------------------------------------------------------------------------------
# Author.....: Wolf Machowitsch
# last update: 1999 03 08    by: Wolf Machowitsch
# ------------------------------------------------------------------------------
# Revision Log:
# - 0.99   1999 03 08   Original Creation
#                       -
#
# - 1.00   1999 03 24   Production Release
#                       minor Code refinements, debugging
#
# ------------------------------------------------------------------------------
# Usage:
#     f_Round num parm1 [ int digits ]
#
#     Example:  f_Round 3.1415926 3      # rounds to 3 digits, giving 3.142
#               f_Round $var             # default for digits is zero, $var
#                                        # is rounded to an int
#
#
# Prerequisites:
# -   to use this function, the FPATH variable must be set
#
# -   functional dependencies: f_CheckNumeric()
#                              f_CheckInteger()
#
# ------------------------------------------------------------------------------
# Documentation:
#     f_Round() takes the first (integer) parameter and rounds it to the
#     number of digits AFTER the decimal point given in $2. If no $2 is
#     supplied the default value of 0 is assumed and $1 is rounded to an
#     integer.
#     The rounding is performed using the common algorithm of adding 5 to
#     the digit to the right of the digit to round and then truncating the
#     digits right to this.
#
#     Parameters: num parm1      a char representing a number
#                 int digits     an integer representing the numbers of
#                                decimals to remain after rounding
#
#     returns:    0: no error
#                 1: type error, parm1 not a number or $2 not an int
#                 2: internal error, no parameter supplied
#
# ------------------------------------------------------------------------------
# known bugs:
#
# -   it is not possible to round to digits before the decimal point
#
# ------------------------------------------------------------------------------
# ......................(C) 99 Wolf Machowitsch ................................
# ------------------------------------------------------------------------------

f_Round ()
{

$chFullDebug
                                                 # internal variables
typeset -i iRetVal=0                             # return value (see docu)
typeset    nValue="$1"                           # value to round
typeset -i iDigits="$2"                          # number of digits
typeset -i iDigit2=0                             # for the rounding
typeset    nAdd="0."                             # for the rounding
typeset -i iCnt=0                                # general counter

if [ -z $iDigits ] ; then                        # set default for iDigits
     iDigits=0
fi

if [ $# -lt 1 ] ; then                           # parameter check
     iRetVal=2
else
     if [ $(f_CheckNumeric $nValue; print $?) -gt 0 ] ; then
          iRetVal=1
     fi
     if [ $(f_CheckInteger $iDigits; print $?) -gt 0 ] ; then
          iRetVal=1
     fi
fi
if [ $iRetVal -gt 0 ] ; then                     # exit on param. error
     return $iRetVal
fi
iDigit2=$((( iDigits+1 )))

(( iCnt=0 ))
while [ $iCnt -lt $iDigits ] ; do
     nAdd=$(print "$nAdd"0)
     (( iCnt += 1 ))
done
nAdd=$(print "$nAdd"5)

                                                 # calculate rounded value
nValue=$( print "scale=$iDigits; $( print "scale=$iDigit2; $nValue + $nAdd" |\
                                    bc \
                                  ) / 1" | \
          bc \
        )

print "$nValue"

return $iRetVal
}
# --- EOF f_Round