Ĝavo (Java) bajta kodoj kaj retumilo

what is name for ‘’ <> ’’ symbol ?

You mean ◊? It’s a lozenge.

You mean ◊? It’s a lozenge.

Could be a reference to David using the less than greater than combo in the absence of a single symbol equal crossed out. Or pling equal.

Could be a reference to David using

Oh, whoops. Took that a little too literally. ;-)

Yeah, in the world of C-like languages, the characters != mean “not equals” (very literally as ! is a negation and = is obvious).

While in the world of BASIC like languages, one may often find <> used instead. The logic here is that it isn’t =, it isn’t <, and it isn’t > either. Therefore it is not equals.

The proper mathematical symbol is ≠, so Haskell uses a rather literal ASCII equivalent /= (though this means something entirely different in C!).

Finally, you may recall from DavidS’ discussion about command line options where a ~ prefix was used to negate the option specified. Lua uses this logic to have ~= (literally a negated equals) perform the same function.

All of these are used in software to check to ensure that this is not the same as that, and when humourously used in forum posts, it means that the two things specified are not the same.

Living <> Dead.
Male != Female.
Drunk ~= Sober.

Frequently used in the context of RISC OS <> Linux.

Frequently used in the context of RISC OS <> Linux.

There’s always the
code size: RO < Linux
and time taken for process in a single core: RO < Linux

Or
time taken to port to a new board/architecture: RO > Linux

In C, the double equals is a comparison (is this == that) while the single equals is an assignment.

So,

if (myval = 3)
{
   printf("MyVal is three!\n");
};

will print “MyVal is three!” regardless of what myval actually was, because it is now three.

What is happening is that the if statement is evaluating the expression which is actually setting myval to 3. Since the value set is non-zero, the evaluation is true, which means the conditional code is executed.

In the olden days, people used to use Yoda code to detect these sorts of problems, namely if (3 = myval) because you can’t assign a number (not even in C!), but these days any competent compiler will warn you that this is happening. Note the italics on the warning, it’ll compile because even though it’s gibberish, it’s legal C.

The more I see of these “strangenesses” of C, the more convinced I am that Dennis Ritchie may have been a couple of sandwiches short of a picnic.

Steve: https://en.wikipedia.org/wiki/Duff%27s_device