How can decimal values be totalled in a Windows batch file for loop

I have been trying to read a comma delimited csv file and total a value from each record using the code below that I have put together from various searches:

@echo off
setlocal EnableDelayedExpansion

set "grandtotal=0"

rem Process the file:
call :ProcessFile < %1
exit /B

:ProcessFile
set /P line=
set "total=0"

:nextLine
set line=:EOF
set /P line=
if "!line!" == ":EOF" goto :EOF
set i=0

for %%e in (%line%) do (
    set /A i+=1
    for %%i in (!i!) do (
        if %%i==4 (
            echo "value of e - " %%e
            set /A htot=+%%e
            echo "value of htot - " %htot%
        )
    )
)

goto nextLine
exit /B

The test csv file contains 4 records with the value in the 4th of 7 fields. I now have a few problems:

The first record is being skipped. No idea as to why. The data in the file should be reading the values of 187.55, 109.48, 612.82, 1028.81 for a total of 1,938.66.
The totalling of the record is not occurring. I am getting a Missing operator. error on the Set /A htot=+%%e
Although I am getting that error, the variable htot does seem to get populated, but with the previously read value.

This is the screen output when I run the batch file:

C:\DOS Stuff>try6 testf.csv
"value of e - " 109.48
Missing operator.
"value of htot - "

"value of e - " 612.82
Missing operator.
"value of htot - " 109
 
"value of e - " 1028.81
Missing operator.
"value of htot - " 612

Solution

Sadly, you haven't given us an obfuscated example of your data file contents, so I made a sample file containing this data:

xyz,"opq,yyy","rsj",187.55,whatever,junk
xyz,"opq,yyy","rsj",109.48,whatever,junk
xyz,"opq,yyy","rsj",612.82,whatever,junk
xyz,"opq,yyy","rsj",1028.81,whatever,junk

The code I devised was

@ECHO OFF
SETLOCAL ENABLEDELAYEDEXPANSION
SET /a characteristic=0,mantissa=0

FOR /f "usebackqdelims=" %%e IN ("%~1") DO (
 SET /a field=0
 FOR %%o IN (%%e) DO (
  SET /a field+=1
  IF !field!==4 FOR /f "tokens=1,2delims=." %%b IN ("%%o") DO SET /a characteristic+=%%b,mantissa=mantissa+1%%c-100
 )
)
SET /a characteristic+=mantissa/100,mantissa=(mantissa %% 100)+100
SET "result=%characteristic%.%mantissa:~-2%"

ECHO %result%

GOTO :EOF

So - to explain:

Note that it is valid to separate value assignments with a comma in set /a.

Read the data file, line-by-line into %%e. My actual command for running this code was q79403729 "u:\your files\q79403729.txt". The ~ strips the quotes from %1, the result is then quoted (so it doesn't matter whether %1 was quoted or not) and the option usebackq used to tell for that the quoted string is a filename, not a literal. (for /? for documentation)

Then use %%o to process %%e as a simple list

Pick the fourth field from the list and use the delimiter . to tokenise %%o, quoted, to be used as a literal into %%b and %%c and add these to the accumulators characteristic and mantissa. Since %%c may contain a leading 0, then that would cause it to be interpreted as octal, raising errors for .08 and .09, then the standard solution is to prefix %%c with 1 and subtract 100.

Finally, adjust for mantissa > 100, ensuring mantissa has 100 added to (its original value mod 100) so that it will be 3 characters long, then the result is bolted together using characteristic, a dot, and the last 2 digits of mantissa

Note that this would need to be adjusted if the field in question does not have a . or contains but one digit after the . and also if a field may be absent from the source data.