#!/bin/bash

shopt -s extglob

# Bash arithmetic is in 64-bit integers, from -2^63 to 2^63-1.
# We emulate floating point arithmetic with paired integers for integer and
# fractional part; we work to 9 figures as 2^63~=9.22e18. 
# A better implementation would use true floating-point arithmetic.
function flop() {
	local op=$2
	local x=$1
	local y=$3
	local sig mod num ipart fpart places raise
	local a
	for a in x y; do
		if [[ ${!a} == -* ]]; then
			sig=-
			mod=${!a:1}
		elif [[ ${!a} == +* ]]; then
			sig=+
			mod=${!a:1}
		else
			sig=+
			mod=${!a}
		fi
		mod=${mod/#+(0)}; [[ "$mod" ]] || mod=0
		num=${mod/.}
		case ${mod} in
		+([[:digit:]])?(.))
			ipart=${mod/.}; fpart=0; places=0;;
		.+([[:digit:]]))
			ipart=0; fpart=${mod/.}; places=${#fpart};;
		+([[:digit:]]).+([[:digit:]]))
			ipart=${mod/%.*}; fpart=${mod/#*.}; places=${#fpart};;
		*)
			num=0; ipart=0; fpart=0; places=0;;
		esac
		fpart=${fpart/#+(0)}; [[ "$fpart" ]] || fpart=0
		ipart=$sig$ipart; fpart=$sig$fpart
		# Pure evil {^_^}
		local name
		for name in sig mod num ipart fpart places; do
			eval $a$name=${!name}
		done
	done
	case $op in
	[+-])
		ipart=$((xipart $op yipart))
		places=$((xplaces > yplaces ? xplaces : yplaces))
		if [[ $places -ge 17 ]]; then
			# Include sign in length
			xfpart=${xfpart:0:17}
			yfpart=${yfpart:0:17}
			xplaces=$((xplaces > 16 ? 16 : xplaces))
			yplaces=$((yplaces > 16 ? 16 : yplaces))
			places=16
		fi
		fpart=$((xfpart * 10 ** (places - xplaces) $op yfpart * 10 ** (places - yplaces)))
		if [[ $fpart -lt 0 ]]; then
			ipart=$((ipart - 1))
			fpart=$((10 ** places + fpart))
		elif [[ $fpart -gt $((10 ** places)) ]]; then
			ipart=$((ipart + 1))
			fpart=$((fpart - 10 ** places))
		fi
		if [[ ${#fpart} -lt $places ]]; then
			fpart=$((10 ** (places - ${#fpart})))$fpart
			fpart=${fpart:1}
		fi
		ipart=${ipart/#+}
		fpart=${fpart/%+(0)}
		echo $ipart.$fpart
		;;
	[×])
		places=$((xplaces + yplaces))
		if [[ $places -ge 18 ]]; then
			xnum=${xnum:0:9}
			ynum=${ynum:0:9}
			places=$(((xplaces > 8 ? 8 : xplaces) + (yplaces > 8 ? 8 : yplaces)))
		fi
		num=$((xnum * ynum))
		if [[ ${#num} -ge $places ]]; then
			ipart=${num:0:$((${#num} - places))}
			fpart=${num:$((${#num} - places))}
		elif [[ ${#num} -eq $places ]]; then
			ipart=0
			fpart=$num
		else
			ipart=0
			fpart=$((10 ** (places - ${#num})))$num
			fpart=${fpart:1}
		fi
		if [[ $xsig == $ysig ]]; then sig=; else sig=-; fi
		fpart=${fpart/%+(0)}
		echo $sig$ipart.$fpart
		;;
	[÷])
		if [[ $ynum -eq 0 ]]; then
			echo "Division by zero" >&2
			return 1
		fi
		raise=$((19 - ${#xnum}))
		num=$(((xnum * 10 ** raise) / ynum))
		places=$((raise + xplaces - yplaces))
		if [[ ${#num} -ge $places ]]; then
			ipart=${num:0:$((${#num} - places))}
			fpart=${num:$((${#num} - places))}
		elif [[ ${#num} -eq $places ]]; then
			ipart=0
			fpart=$num
		else
			ipart=0
			fpart=$((10 ** (places - ${#num})))$num
			fpart=${fpart:1}
		fi
		if [[ $xsig == $ysig ]]; then sig=; else sig=-; fi
		fpart=${fpart/%+(0)}
		echo $sig$ipart.$fpart
		;;
	esac
}

declare -a stack
while read line; do
	[[ "$line" ]] || exit 0
	stack=( )
	line=${line//\\*/×}
	for token in ${line//\//÷}; do
		case $token in
		[÷×+-])
			if [[ ${#stack[@]} -gt 1 ]]; then
				result=$(flop ${stack[1]} $token ${stack[0]})
				stack=( $result ${stack[@]:2} )
			else
				echo "Stack underflow"
			fi
			;;
		?(-)+([[:digit:].]))
			stack=( $token ${stack[@]} )
			;;
		*)
			echo "Bad operator: $token"
		esac
	done
	[[ ${#stack[@]} -gt 0 ]] \
		&& echo ${stack[$((${#stack[@]}-1))]}
done