CheckSum(field 10)

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1

Imported from previous forum

2

[ original email was from Mikhail Stotland - m5373@hotmail.com ]
Hi,
I would like to ask you about something what I have a problem with, I am
working on the FIX protocol 4.0 and I have to calculate a CheckSum(field
10), I found code in C++, and I am VB programmer. I would really appreciate
if you could help me with it.
Thank you.

3

I’m not a Visual Basic person. I assume you are reviewing Appendix B - CheckSum Calculation which provides a C language sample code fragment. VB may even have a built-in checksum method/function.

What this code does is:

  • take the FIX message stream (string)

  • loop through each byte (character):

    1. determine the integer value of that byte (e.g. ‘A’=65, ‘a’=97, ‘.’=46, note will be <= 256)
    2. accumulate (continue to add values to a variable) the integer value of that byte to a variable in order to obtain the sum of the integer value of each byte in the FIX message stream

  • compute the modulus (integer of the remainder following division also known as "mod" (C/C++ and Java use "%" for this)) of the sum obtained above when divided by 256

  • take the modulus integer value (will always be less than 256 since it was mod’d by 256) and represent it as a 3 character sting with leading zeros if necessary

  • use the above 3 character string as the value for Checksum (tag 10)

Hope that helps.

> Hi,
> I would like to ask you about something what I have a problem with, I am
> working on the FIX protocol 4.0 and I have to calculate a CheckSum(field
> 10), I found code in C++, and I am VB programmer. I would really appreciate
> if you could help me with it.
> Thank you.
>