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???
10/22/10 09:07
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 		 #179268 - Corrigendum
Responding to: ???'s previous message
Jan Waclawek said:
Andy Neil said:
A for loop always take the value of the 3rd (sic) expression as the condition on whether to exit or continue the loop: if the value of the 3rd (sic) expression is zero, the loop exits; otherwise, it continues.

Please replace 2nd for 3rd in the above sentence.


D'oh!

You are right - I have now corrected that (with a note)

From the 'C' standard:

ISO/IEC 9899:1990 (The 'C' standard) said:

6.6.5.3 The for statement

Except for the behavior of a continue statement in the loop body,
the statement
Save This Code
for (  expression-1 ;  expression-2 ;  expression-3 )  statement

and the sequence of statements
Save This Code
   expression-1 ;
   while( expression-2 ) 
   {
      statement
      expression-3 ;
   }

are equivalent.


The 'C' standard goes on to say,
Both expression-1 and expression-3 may be omitted. Each is evaluated as a void expression.
An omitted expression-2 is replaced by a nonzero constant.


hence:
Save This Code
 for( ;; )

is equivalnt to:
Save This Code
 while( 1 )


List of 49 messages in thread
TopicAuthorDate
p89lpc936 keil programming help required.            01/01/70 00:00      
   magic code?            01/01/70 00:00      
      mov 0A5H,#0FFH            01/01/70 00:00      
   a glaring difference            01/01/70 00:00      
      a glaring difference            01/01/70 00:00      
         what happens if            01/01/70 00:00      
            what happens if            01/01/70 00:00      
               BiDir or PushPull            01/01/70 00:00      
               I leave it to you            01/01/70 00:00      
                  magic code?            01/01/70 00:00      
                  I leave it to you            01/01/70 00:00      
                     1) formatted, 2)commented, 3) correct            01/01/70 00:00      
                        1) formatted, 2)commented, 3) correct            01/01/70 00:00      
                           it is STILL two different things            01/01/70 00:00      
                              Apples and Orange Juice            01/01/70 00:00      
                                 Please focus on the problem i have            01/01/70 00:00      
                                    Software delay loop in C is a no-no            01/01/70 00:00      
                                       Software delay loop in C is a no-no            01/01/70 00:00      
                                          Reduce problem into smaller problems            01/01/70 00:00      
                                             Reduce problem into smaller problems            01/01/70 00:00      
                                             Simulator vs real hardware            01/01/70 00:00      
                                             Current limits            01/01/70 00:00      
                                             Per Westermark's previous message            01/01/70 00:00      
                                                Delay speed            01/01/70 00:00      
                                                   Elaborate            01/01/70 00:00      
                                                      tried 5 for the '51 and Keil won            01/01/70 00:00      
                                    the problem you have is ...            01/01/70 00:00      
                                       the problem you have is ...            01/01/70 00:00      
                                          do you have LEDs connected to the simulator?            01/01/70 00:00      
                                          not executing on actual hardware while simulator is fine            01/01/70 00:00      
                                    Oh So Focused            01/01/70 00:00      
   Double-post            01/01/70 00:00      
   Are you using the limited version of KEIL? the for loop....            01/01/70 00:00      
      valid C            01/01/70 00:00      
         Thats the point            01/01/70 00:00      
            nope            01/01/70 00:00      
               I wouldnt trust it            01/01/70 00:00      
                  if you do not trust it ....            01/01/70 00:00      
               And if you trust it so much why doesnt it work?            01/01/70 00:00      
                  And if you trust it so much why doesnt it work?            01/01/70 00:00      
                     trust, yes, but knowledge also required            01/01/70 00:00      
                  wait call + assumptions about two-complement, ...            01/01/70 00:00      
                     The C Standard            01/01/70 00:00      
                        who is "you"?            01/01/70 00:00      
            Yes, you can!            01/01/70 00:00      
      Quite common loop design for bit operations            01/01/70 00:00      
      for( expression-1; expression-2; expression-3 ) [ed]            01/01/70 00:00      
         erratum            01/01/70 00:00      
            Corrigendum            01/01/70 00:00      

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