Programming Trivia Pop Quiz: Make it TRUE!

[altenbach]

According to Wikipedia, "Trivia" refers to bits of information, often of little importance.

(Questions posted here are very unlikely to show up on a CLAD exam, for that we have these other discussions)

I guess we could have an occasional quick pop quiz that should post no problems to the seasoned programmer, but might stump some of the newcomers for a few minutes. So here is the first one:

QUESTION: Given the code shown in the image, find four different inputs that will make the output TRUE when the program is executed.

(Any numeric datatype is allowed, that's why the wire is currently a generic black. All primitives are straight from the palettes. No fake modifications or hidden custom code).

[crossrulz]

Since I was already privy to the discussion that prompted this, I will give a hint.

Spoiler

There is a value for each of the four integer data types (I8, I16, I32, and I64).

[Gregory]

You said any numeric datatype is allowed, but that's not completely true 🙂

[altenbach]

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@Gregory wrote:

You said any numeric datatype is allowed, but that's not completely true 🙂

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Broken wires are allowed, but it would be difficult to generate a TRUE (i.e. the required task!) with broken code. 😄

[jwscs]

so i could do it for integers, not for floats, and i am quite confused.

i hope you will give a nice explanation

Spoiler

seems my twos-complement knowledge has shrunk to a peanut 😉
the absolute value of -128 is not representable in i8,
the normal operation would be to negate all bits and add 1,
but that doesn't seem to happen here.

[crossrulz]

jwcs,

Spoiler

Do the math in hex and it makes a lot more sense.  Take the I8 as an example.  -128 = 0x80.  Invert all bits yields 0x7F.  Add 1 and you are left with 0x80.

[jwscs]

@crossrulz

Spoiler

thx.. as i said befor .. peanuts 😉 .. i read up on the twos complement now it makes sense and is the "normal" two complements way

[JÞB]

Time for another

[Gregory]

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@JÞB wrote:

Time for another

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Spoiler

[crossrulz]

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@JÞB wrote:

Time for another

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That's a Rube Goldberg.  I can replace that with one node.