Re^4: A way to avoid repeated conditional loops

I already pointed out that AR's version is wrong. You can't rely on readline returning EOF or errors more than once.

I thought mine was better than JavaFan's because it lead to the elimination of the duplicate "g()", but that turned out to be a mistake (as per my earlier update).

I still prefer mine over JavaFan's, though. Since mine flows from top to bottom, it requires less skipping around to follow the code.

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Re^5: A way to avoid repeated conditional loops by jffry (Hermit) on Aug 24, 2011 at 21:46 UTC
Ah! Now I see what you're saying. Using AR's code, suppose the file is empty, then the very first `while (<FILE>)` will return `EOF`, then the code flows to the second `while (<FILE>)`. There, even though the file pointer is at the end of the file, the `<>` operator won't return an `EOF` a second time. And the code in that second `while` loop will get executed when it should not. Thinking of it this way, I can now see how both yours and JavaFan's code avoid that trap. Thanks.	[reply]

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Re^5: A way to avoid repeated conditional loops
by jffry (Hermit) on Aug 24, 2011 at 21:46 UTC

Ah! Now I see what you're saying.

Using AR's code, suppose the file is empty, then the very first while (<FILE>) will return EOF, then the code flows to the second while (<FILE>). There, even though the file pointer is at the end of the file, the <> operator won't return an EOF a second time. And the code in that second while loop will get executed when it should not.

Thinking of it this way, I can now see how both yours and JavaFan's code avoid that trap. Thanks.

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