Look again at your first loop. You are comparing idx, which is nonzero,
to 0
which will always give you false, so the loop will never execute. It's
like
a while loop with a null condition.
I didn't look at the second loop but I am guessing it does the same type
of
thing.
Just mentally trace the flow and it's not hard to see.
--le
----- Original Message -----
From: "Alex Hall" <mehgcap@xxxxxxxxx>
To: <programmingblind@xxxxxxxxxxxxx>
Sent: Tuesday, October 06, 2009 5:44 PM
Subject: for loop being skipped!
Hi all,
I have a very long program in javascript that gets a bunch of stats
functions on a list (or two lists) of numbers. Currently I am trying
to allow for frequencies, so a user could type
1 2 2 2 3
or just
1 2f3 3
to be the same thing; f is frequency and means to repeat the number
before the f as many times as the number after. "str" is my string in
the code segment below. The idea is to find the first f in the string
and get its index (the idx variable), then start there and go
backwards until I find a space; once I hit a space, I can get the
characters between it and the index of f, and that is the number to be
repeated. I then do the same thing, but going forward from the f
index, to see how many times I should repeat the number. However,
neither for loop is running!! I have never seen a code segment skipped
before, unless it is in a conditional statement (which is not the case
here). I have the whole thing in a try/catch (not shown), but that is
not picking up any errors and the alert to tell me the start and stop
variables is working, except both equal 0. If you want to test it,
just initialize str to something like
1 2f3 4
and see what happens. Again, this is javascript.
//get the first index of "f"
var idx=str.indexOf("f");
var start=0;
var stop=0;
var i=idx;
//move backward from there until we hit a space
alert("about to loop: "+i+", "+idx);
for(i=idx;i==0;i--){
alert("first loop"); //to see if it is ever entered
if(str.charAt(i)==" " || i==0){
//space found or start of list, so end
alert("getting start");
start=i;
break;
}
}
//now do the same thing, but moving forward
for(i=idx,l1=str.length;i<l1;i++){
if(str.charAt(i)==" "){
stop=i;
break;
}
}
alert(start+" to "+stop);
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