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Requan
Joined: 11 May 2008
Posts: 74
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| Different way to convert four digits to one int16 |
 Posted: Fri Jul 20, 2012 6:51 am |
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Hi,
I received in buffer via TCP/IP four digits in dec e.g:
| Code: |
buffer[0] = 54;
buffer[0] = 48;
buffer[0] = 49;
buffer[0] = 55;
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to convert to in16 i made calculation:
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int16 Addres = ((buffer[4]-48)*1000) + ((buffer[5]-48)*100) + ((buffer[6]-48)*10) + (buffer[7]-48);
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What do You think about this method ? is it easer way to do it? |
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temtronic
Joined: 01 Jul 2010
Posts: 9219
Location: Greensville,Ontario
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| Posted: Fri Jul 20, 2012 7:34 am |
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While there are probably N+1 ways to solve the problem..
you have to ask yourself...
Q1: Does it work exactly the way you need it to ?
Q2:Do you understand how it works ?
Q3:Is it fast enough for your application?
Q4: Is it small enough?
If you answered YES to all of the above, then there is no need to change the code.
Sure there are other ways to do it, but if 'happy' with your solution why change ? |
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SherpaDoug
Joined: 07 Sep 2003
Posts: 1640
Location: Cape Cod Mass USA
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| Posted: Fri Jul 20, 2012 7:35 am |
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1) Make ABSOLUTELY sure the input values are in the correct range. If not it could be a nightmare to debug. Consider using the function isdigit() or isxdigit().
2) Use ((buffer[4]-'0')*1000) instead of ((buffer[4]-48)*1000). In the future you or someone else supporting your code may wonder where that magic number 48 came from?
_________________
The search for better is endless. Instead simply find very good and get the job done. |
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Requan
Joined: 11 May 2008
Posts: 74
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| Posted: Fri Jul 20, 2012 7:57 am |
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When i have 4 digit to convert it works ok, but when i have less it doesn't.
I can use "if statement" but maybe it is better solution |
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SherpaDoug
Joined: 07 Sep 2003
Posts: 1640
Location: Cape Cod Mass USA
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| Posted: Fri Jul 20, 2012 8:32 am |
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isdigit() should tell you if there is a valid digit available.
_________________
The search for better is endless. Instead simply find very good and get the job done. |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Fri Jul 20, 2012 8:39 am |
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| Requan wrote: | | When i have 4 digit to convert it works ok, but when i have less it doesn't. |
So how do you know when there are less than 4 digits?
The standard method would be to have the text as a string, i.e. your array is to have a terminating 0x00 as the last character. That way you can use the C-function atoi() for the conversion and it will handle strings with all number of digits. |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Fri Jul 20, 2012 11:57 am |
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| Quote: |
That way you can use the C-function atoi() for the conversion
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for 16 bits it is atoL()
but when i don't KNOW what value i am expecting, i tend to do this:
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int32 temp;
temp=atoi32(instrng);
// then cast the eventual type DOWN as i may need
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