#Enter and add in the Item detail, Item Price and Quantity Purchased into the system.
add_item()
{
  echo "Add Item: You will be prompted for 3 items:"
  echo "- Item Description, Unit Price, Quantity Purchased -"
  echo
  echo -en "Item Description:"
  read product
  echo -en "Unit Price:"
  read Unit_Price
  echo -en "Quantity:"
  read Quantity
  Date_Purchased=$(date +"%d %b %Y")  
  
  echo "${product}:${Unit_Price}:${Quantity}:${Date_Purchased}" >> $POS
}
#i am printing out all the daily sales in a day   print_dtotal
#i am printing out all the grand total sales of all days  print_gtotal
summary_items()
{
  
  print_dtotal
 
  print_gtotal
  
  print_dtotal | sort -f4| while read z
    do
        echo $z | cut -f4 -d' '
        return 0
    done
  echo
  echo -en "Press Enter to continue..."
  read
}
print_dtotal()
{
  count=0
  grep -i : $POS | cut -d: -f4 | sort -u | while read i
    do
        dtotal=0
    grep -i "$i" $POS | while read x
        do
            count=`expr $count + 1`
            temp1=`echo $x | cut -d: -f2 | cut -c2-`
            temp2=`echo $x | cut -d: -f3`
            temp3=`calcu_m $temp1 $temp2`
                        dtotal=`calcu_a $dtotal $temp3`
            n=`num_lines "$i"`
               if [ "${n}" -eq "${count}" ]; then
                echo  $i"        $"$dtotal
              fi
        done
    done 
}
print_gtotal()
{
  gtotal=0
  grep -i : $POS | while read x
    do
        temp1=`echo $x | cut -d: -f2 | cut -c2-`
        temp2=`echo $x | cut -d: -f3`
        temp3=`calcu_m $temp1 $temp2`
                gtotal=`calcu_a $gtotal $temp3`
        n=`num_lines "$i"`
           if [ "${n}" -eq "${count}" ]; then
            echo  "Grand Total      $"$gtotal
          fi
        count=`expr $count + 1`
    done 
}
calcu_a()        # add 2 decimal numbers $1 $2
{
    x1=`echo $1 | cut -d. -f1`
    x2=`echo $1 | cut -d. -f2`
    y1=`echo $2 | cut -d. -f1`
    y2=`echo $2 | cut -d. -f2`
    x1=`expr $x1 + $y1`
    x2=`expr $x2 + $y2`
    x3=`expr $x2 \/ 100`
    x1=`expr $x1 + $x3`
    x2=`expr $x2 \% 100`
    echo $x1"."$x2
}
calcu_m()        # multiply 2 decimal numbers $1 $2
{
    x1=`echo $1 | cut -d. -f1`
    x2=`echo $1 | cut -d. -f2`
    y=`echo $2`
    x1=`expr $x1 \* $y`
    x2=`expr $x2 \* $y`
    x3=`expr $x2 \/ 100`
    x1=`expr $x1 + $x3`
    x2=`expr $x2 \% 100`
    echo $x1"."$x2
}