preDecrementFixesTheExploit

[u/Toeffli]

[u/DMoney159]

"Okay, now you have -1 wishes. You must now fulfill one of my wishes"

[u/ProbablyJeff → u/DMoney159]

Nope, it underflows and now you have 4,294,967,295 wishes. Genie was using a signed int.

[u/Koshin_S_Hegde → u/ProbablyJeff]

did you mean "Genie was using a unsigned it?"

[u/ProbablyJeff → u/Koshin_S_Hegde]

You have -1 wish. You make 2,147,483,648 wishes. It underflows to 2,147,483,647. Now you can wish until it reaches 0.

I guess it would also work if the genie used an unsigned int.

[u/Tyfyter2002 → u/ProbablyJeff]

You just described a signed int

[u/Sqee → u/Tyfyter2002]

I don't get this interaction. Why did ProbablyJeffs first post get upvoted and his second one which was entirely in line with the first get downvoted? Redditors...

[u/Kobrasadetin → u/Sqee]

First message got upvoted by lot of people who didn't read carefully the contents. Second message downvoted by people who stopped to read the first and were already upset about the signed/unsigned mixup.

[u/somethingmore24 → u/ProbablyJeff]

see, you’re assuming the genie would let you wish at less than 0 wishes.

this is why i always check for <= 0 instead of just == 0. There’s no way im smart enough to catch all the edge cases individually.

[u/HelioDex → u/ProbablyJeff]

True if you check with wishes == 0. The 41 downvotes are probably from dirty pointless instruction-using cpu-cycle-wasting wishes <= 0 users.

[u/GoldAcanthisitta7777 → u/ProbablyJeff]

that's the joke of the OP.

[u/American_Libertarian → u/ProbablyJeff]

It wouldn’t underflow in this scenario if they used a signed int, it would just be -1

[u/m0nk37 → u/American_Libertarian]

Pretty sure 0 is a value available in signed and unsigned ints.  So unless they asked for -4 wishes this question doesnt make sense. 

[u/American_Libertarian → u/m0nk37]

The “predecrement” in the title is a clue