On 01/11/2013 12:20 PM, A J Stiles wrote:
I try to write comparisons as != where possible and then there is no
confusion and less mistakes possible.
Most compilers will warn on the example below now.
On Friday 11 January 2013, penguin wrote:
quick question that leaves alittle confusion here. Im confused on the
difference or when to use the other if i have 1 = sign or 2 == signs .. so
If i had
exten => _XXXX,1,answer()
same=> n,Set($[${a}==1]?true:false] <--double equal sign
same => n(true),Goto(main,s,1)
same=> n(false), Hangup()
would this be saying the same thing as above then?
exten => _XXXX,answer()
same=> n,Set($[${a}=1]?true:false] <-- single equal sign
in essence wouldn't i get the same result ? im confused on the double and
single equal sign and when to use the difference of the two. Would i get
the same result in both these expressions?
Generally, one = sign means you're telling. Two == signs means you're asking.
It's amusing (for sadists) to see ex-BASIC programmers trip up over this and
write something like this:
if (denominator = 0) {
printf ("Can't divide by zero!\n");
} else {
answer = numerator / denominator
};
This will never print "Can't divide by zero!" because you are actually
assigning a value to a variable right there in the conditional, and returning
the assigned value. Since this is zero, the if() will fail and drop through
to the else clause -- and then, just to confuse you, the program will crash
with "Floating point exception" anyway.
--
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