Robin Vickery schreef:
2008/7/15 tedd <tedd.sperling@xxxxxxxxx>:
I said:
"Round-off errors normally don't enter into things unless your doing
multiplication and division operations."
And that is not "Bull" -- it's true. You can add and subtract all the
floating point numbers (the one's we are talking about here) you want
without any rounding errors whatsoever.
$ php -r 'echo 0.7 - 0.2 == 0.5 ? "true\n" : "false\n";'
false
The operation you do isn't important. You just can't represent certain
numbers exactly in binary, just as you can't represent 1/3 exactly in
decimal. They have to be rounded internally.
which makes php casting so much fun:
$ php -r 'echo (string)(0.7 - 0.2) == 0.5 ? "true\n" : "false\n";'
true
-robin
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