4 ms·

I've been programming for 15 years and had to google what NAND was. Had a sense of XOR

by brailsafe 4y ago

dpz 4y ago
- anon84873628 4y ago
  The truth is that you can be a successful computer software developer and not need to know much at all about how computers work. Or even how things like compilers work. Some of us never even studied in a CS program - gasp!
  - SmellTheGlove 4y ago
    It’s all layers of abstraction, right? While it’s good to have a basic understanding of how the whole stack works, it’s also a feature and a goal of those building the lower levels to enable others to operate at higher levels independent of that knowledge. Taking this away from software for a second, I know a hell of a lot of people skilled in their professions that have no idea exactly how their cars work but they drive them just fine.
  - dpz 4y ago
    i also never studied CS but find it quite odd they didn't even stumble across them in 15 years
    - brailsafe 4y ago
      I've stumbled across and used them, but it never occurred to me to actually check what NAND stood for.
deleted 4y ago
[deleted]
groffee 4y ago
That's not something you should be so quick to tell people.
- ch4s3 4y ago
  Oh come on! There are a lot of types of programming and most of them exist pretty far from logic gates. The previous poster probably understands the concepts from their work but doesn’t relate them to logic gates.
  - brailsafe 4y ago
    Ya that's basically what I meant. The concepts are arguably unavoidable if you've done enough.
- brailsafe 4y ago
  Heh, roasted. I know you're being a bit facetious, but it's not like I haven't used them, but in terms of the acronyms and maybe actually using them as bitwise operations, it's something I've rarely needed in JS programming. If you aren't being facetious, then you might need to work on humility
thendrill 4y ago
You would be surprised how much more relevant info programmers miss... Example, most programmers I know have no idea when a variable gets allocated on the stack and when it's on the heap. Let's not talk about how many dont even know what a (stack overflow)[https://en.m.wikipedia.org/wiki/Stack_buffer_overflow https://en.m.wikipedia.org/wiki/Stack_buffer_overflow] is...
- dhosek 4y ago
  I remember being shocked to discover that a recent CS grad could not implement a factorial function using recursion. I can understand why you wouldn’t want to do that, but to not be able to do it?
  - lumost 4y ago
    a lot of CS undergrads compress out recursion knowledge. They learn that most recursion is best skipped in favor of iteration/dp, and they learn that they should implement things efficiently. It’s possible the undergrad assumed you were referring to an efficient recursive algorithm or simply forgot most recursion.
    - dhosek 4y ago
      No, I was quite explicit, and seriously, is it really that hard to write something along the lines of if (i<=1) return i; else return factorial(i-1)*i; It wasn't meant to be a trick or trap, it was the simplest recursive function I could think of and it’s not like I was asking him to implement a stack.
  - brailsafe 4y ago
    Heh, I just did the DS+A section of a Faang interview, and got the time and space complexity of an optimal solution more or less correct, as well as most of a recursive binary search implementation, but not quite there. I stumble with recursion because syntactically it's something you either have to use a lot or deliberately practice to have a keen sense of return values imo. Probably won't get an offer because of that. Do I feel like as a frontend engineer I really need that knowledge? Not really. I could work it out for work purposes if I needed to tho. I'd be practicing it just to pass interviews.
wongarsu 4y ago
To be fair, AND, OR and NOT are enough to compute any function, and you can make all the other operators out of a combination of those three. For example A XOR B is just (A OR B) AND (NOT (A AND B)). Knowing things beyond AND, OR or NOT is useful, but not strictly necessary. XOR has useful properties though: with random inputs you get TRUE 50% of the time, allowing you to chain it without trending to 0 or 1; also it's the opposite of bitwise equality. The others aren't that interesting if you aren't dealing with hardware, and their function is obvious if you know the naming convention.
- dhosek 4y ago
  Nah, all you need are nand gates. Everything else can be implemented from those.
  - dan-robertson 4y ago
    Yeah, similarly in mathematics they often like to build everything up from ‘implies’ where the rule is implies(a,b) = or(not(a), b) = nand(a,nand(b, b)).
- OJFord 4y ago
  You only need one of {AND, OR} too. ((a or b) is (not ((not a) and (not b))), and vice versa.)
- deleted 4y ago
  [deleted]
bergenty 4y ago
All the Ns are just the opposites.
_whiteCaps_ 4y ago
If you want to learn more about logic gates, you might like the book "Bebop to the Boolean Boogie". It's aimed at kids but someone with a CS background could fly through it pretty quickly.

I've been programming for 15 years and had to google what NAND was. Had a sense of XOR

dpz 4y ago

anon84873628 4y ago
The truth is that you can be a successful computer software developer and not need to know much at all about how computers work. Or even how things like compilers work. Some of us never even studied in a CS program - gasp!
- SmellTheGlove 4y ago
  It’s all layers of abstraction, right? While it’s good to have a basic understanding of how the whole stack works, it’s also a feature and a goal of those building the lower levels to enable others to operate at higher levels independent of that knowledge. Taking this away from software for a second, I know a hell of a lot of people skilled in their professions that have no idea exactly how their cars work but they drive them just fine.
- dpz 4y ago
  i also never studied CS but find it quite odd they didn't even stumble across them in 15 years
  - brailsafe 4y ago
    I've stumbled across and used them, but it never occurred to me to actually check what NAND stood for.

deleted 4y ago

[deleted]

groffee 4y ago

That's not something you should be so quick to tell people.

ch4s3 4y ago
Oh come on! There are a lot of types of programming and most of them exist pretty far from logic gates. The previous poster probably understands the concepts from their work but doesn’t relate them to logic gates.
- brailsafe 4y ago
  Ya that's basically what I meant. The concepts are arguably unavoidable if you've done enough.
brailsafe 4y ago
Heh, roasted. I know you're being a bit facetious, but it's not like I haven't used them, but in terms of the acronyms and maybe actually using them as bitwise operations, it's something I've rarely needed in JS programming. If you aren't being facetious, then you might need to work on humility

thendrill 4y ago

You would be surprised how much more relevant info programmers miss... Example, most programmers I know have no idea when a variable gets allocated on the stack and when it's on the heap. Let's not talk about how many dont even know what a (stack overflow)[https://en.m.wikipedia.org/wiki/Stack_buffer_overflow https://en.m.wikipedia.org/wiki/Stack_buffer_overflow] is...

dhosek 4y ago
I remember being shocked to discover that a recent CS grad could not implement a factorial function using recursion. I can understand why you wouldn’t want to do that, but to not be able to do it?
- lumost 4y ago
  a lot of CS undergrads compress out recursion knowledge. They learn that most recursion is best skipped in favor of iteration/dp, and they learn that they should implement things efficiently. It’s possible the undergrad assumed you were referring to an efficient recursive algorithm or simply forgot most recursion.
  - dhosek 4y ago
    No, I was quite explicit, and seriously, is it really that hard to write something along the lines of if (i<=1) return i; else return factorial(i-1)*i; It wasn't meant to be a trick or trap, it was the simplest recursive function I could think of and it’s not like I was asking him to implement a stack.
- brailsafe 4y ago
  Heh, I just did the DS+A section of a Faang interview, and got the time and space complexity of an optimal solution more or less correct, as well as most of a recursive binary search implementation, but not quite there. I stumble with recursion because syntactically it's something you either have to use a lot or deliberately practice to have a keen sense of return values imo. Probably won't get an offer because of that. Do I feel like as a frontend engineer I really need that knowledge? Not really. I could work it out for work purposes if I needed to tho. I'd be practicing it just to pass interviews.

wongarsu 4y ago

To be fair, AND, OR and NOT are enough to compute any function, and you can make all the other operators out of a combination of those three. For example A XOR B is just (A OR B) AND (NOT (A AND B)). Knowing things beyond AND, OR or NOT is useful, but not strictly necessary. XOR has useful properties though: with random inputs you get TRUE 50% of the time, allowing you to chain it without trending to 0 or 1; also it's the opposite of bitwise equality. The others aren't that interesting if you aren't dealing with hardware, and their function is obvious if you know the naming convention.

dhosek 4y ago
Nah, all you need are nand gates. Everything else can be implemented from those.
- dan-robertson 4y ago
  Yeah, similarly in mathematics they often like to build everything up from ‘implies’ where the rule is implies(a,b) = or(not(a), b) = nand(a,nand(b, b)).
OJFord 4y ago
You only need one of {AND, OR} too. ((a or b) is (not ((not a) and (not b))), and vice versa.)
deleted 4y ago
[deleted]

bergenty 4y ago

All the Ns are just the opposites.

_whiteCaps_ 4y ago

If you want to learn more about logic gates, you might like the book "Bebop to the Boolean Boogie". It's aimed at kids but someone with a CS background could fly through it pretty quickly.