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May 23rd, 2009
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Need Help with evaluation

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Hello.,
I'm very new in C++, and I have a task to solve.
I have a function:

C++ Syntax (Toggle Plain Text)
  1. void cio_display(const char *str, int row, int col, int len){
  2.   int i;
  3.   cio_move(row, col);
  4.   if(len<=0) {
  5.     cio_putstr(str);
  6.   }
  7.   else{
  8.     for(i=0;i<len && str[i];i++)
  9.       cio_putch(str[i]);
  10.  
  11.     for(;i<len;i++)
  12.       cio_putch(' ');
  13.   }

here iss what i have done:

C++ Syntax (Toggle Plain Text)
  1. void cio_display(const char *str, int row, int col, int len){
  2.  
  3. 	int i;
  4. 	cio_move(row, col);
  5. 	for( i = 0; ((len <= 0) && cio_putstr(str)), (i < len && str[i]); i++){
  6. 	cio_putch(str[i]);
  7. 	}
  8.  
  9. 	for(;i<len;i++)
  10. 	cio_putch(' ');
  11. }

The problem id the function cio_putstr() returns void, thats why lazy evaluation is not possible. Any other thoughts would be greatly appreciated!

Thank you
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May 23rd, 2009
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Re: Need Help with evaluation

I have no idea what you are talking about. What is "lazy evaluation" ? And why does it matter whether cio_putstr() returns void or something else ?
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Sorry, was in the rush and forgot to ask...

sorry was in a rush and forgot to ask., The question is how to rewrite the function w/o using if statement.
Any help would be appreciated
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atman is offline Offline
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May 24th, 2009
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Re: Need Help with evaluation

Um..."while" and "for" come to mind, just need to use a little creativity. Its not that hard.
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kenji is offline Offline
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May 24th, 2009
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Re: Need Help with evaluation

What's a problem?
C++ Syntax (Toggle Plain Text)
  1. for (i = 0;
  2.      len <= 0 && str[i] || str[i] && i < len;
  3.      i++) {
  4.     cio_putch(str[i]);
  5. }
  6. while (i++ < len)
  7.     cio_putch(' ');
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Re: Need Help with evaluation

> To the OP: You say that this function - cio_putstr() returns a void . If this is so, then just why is it in your for loop as a test expression? And could you explain what it - cio_putstr() - is supposed to do?

> To Ancient Dragon: I read about "lazy evaluation" in some book, but I don't remember which one ... Anyway, here is wiki on it.
Last edited by amrith92; May 24th, 2009 at 6:37 am.
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Re: Need Help with evaluation

>just why is it in your for loop as a test expression?
That's a good question
However there is an absolutely senseless condition with comma operator in that snippet, so it does not matter why ...
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Re: Need Help with evaluation

Quote originally posted by amrith92;874959[B ...
>[/B] To Ancient Dragon: I read about "lazy evaluation" in some book, but I don't remember which one ... Anyway, here is wiki on it.

OMG I've been doing that for 50 years and always thought it was called procrastination. Now I know I was just plain lazy
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May 27th, 2009
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Re: Need Help with evaluation

a switch statement??
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May 28th, 2009
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Re: Need Help with evaluation

Click to Expand / Collapse  Quote originally posted by jloundy ...
a switch statement??
What's a cool tip!
Which else C++ control statements are you familiar with?
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This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.
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