u increment after! asigning, so far so good, but for math reasons the interpreter has to keep in mind the 123 you want to assign before increment to the same var. this is absolutely correct what php does here. $num = ++$num; would print 124 the same like $num++; on the other hand this is just bullshit I would release any programmer using that type of code. ralph_deffke@xxxxxxxx <clancy_1@xxxxxxxxxxxx> wrote in message news:8fudc5tc6qvfj4n297kvjlqd3s7sjdkvqb@xxxxxxxxxx > Daevid Vincent is surprised that: > > $num = 123; > $num = $num++; > print $num; //this prints 123 and not 124 ?!! > > To me this is relatively logical. As I understand it, the post-increment operator says "do > something with the variable, and then increment it. The trouble in this case is that we > are doing something irrational; we are copying the number back to itself, and to me it is > reasonably logical (or at least no less illogical than the alternative) to assume that if > we copy it to itself, then increment the original version, the copy will not be > incremented. > > However there is one feature of PHP which, to my mind, is really bad design. How many of > you can see anything wrong with the following procedure to search a list of names for a > particular name? > > $i = 0; $j = count ($names); while ($i < $j) > { if ($names[$i] == $target) { break; } > ++$i; > } > > As long as the names are conventional names, this procedure is probably safe to use. > However if you allow the names to be general alphanumeric strings, it is not reliable. One > of my programs recently broke down in one particular case, and when I eventually isolated > the bug I discovered that it was matching '2260' to '226E1'. (The logic of this is: 226E1 > = 226*10^1 = 2260). > > I agree that I was well aware of this trap, and that I should not have used a simple > comparison, but it seems to me to be a bizarre design decision to assume that anything > which can be converted to an integer, using any of the available notations, is in fact an > integer, rather than making the default to simply treat it as a string. It is also a trap > that it is very easy to fall into if you start off thinking about simple names, and then > extend (or borrow) the procedure to use more general strings. > > And can anyone tell me whether, in the above case, it is sufficient to write simply: > if ((string) $names[$i] == $target), > > or should I write: > if ((string) $names[$i] == (string) $target)? > > (I decided to play safe and use strcmp ().) > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
