• fubo@lemmy.world
    742·
    1 year ago

    Fortran, really.

    In Fortran, variables beginning with the letters i through n have integer type by default, whereas all other letters imply a real-number (floating-point) variable. You can change this by declaring a type, but using i for a real is non-obvious.

    (Hence the old joke, “God is real — unless declared integer.”)

    • Eager Eagle@lemmy.worldEnglish
      342·
      1 year ago

      idk, this arbitrary i-n range behaving differently than other variables sounds like a terrible source of weird bugs to me. I don’t think variable names should ever change a program’s behavior.

      edit:

      Many old Fortran 77 programs uses these implicit rules, but you should not! The probability of errors in your program grows dramatically if you do not consistently declare your variables.

      source

      • Successful_Try543@feddit.de
        29·
        1 year ago

        This comes from early years, when FORTRAN was introduced and the programmers needed to save space in the punch cards. Today, to avoid this possible source of bugs, you usually state “implicit none” in the preamble.

  • juliebean@lemm.ee
    601·
    1 year ago

    in programming, and in mathematics, it’s always been weird to me that frequently paired variables are basically the most easily confused for one another pairs, especially when written quickly or sloppily.

    • i and j
    • x and y
    • m and n
  • Sam@sh.itjust.works
    34·
    1 year ago

    I always like to joke in coding interviews that I really like to make variable names as long as I can so they are very precisely named. Then when I get to a double nested loop I hit them with iterator and jiterator instead of I and j

  • Eager Eagle@lemmy.worldEnglish
    262·
    1 year ago

    Unless they’re indices, do yourself a favor and use meaningful names instead.

    I avoid index iterations the most I can tbh. And for nested loops,i and k is more readable.

    • fidodo@lemm.ee
      121·
      1 year ago

      Even for indexes I do index or something more specific for what it’s indexing. Any simple iteration I just do map or each so the only time I ever need to actually index things is for more complex scenarios in which case it’s worth it to have better names. Also with modem IDEs, auto complete is really good so you don’t need to write a full variable name more than once.

    • Alien Nathan Edward@lemm.ee
      5·
      1 year ago

      When I was a baby coder back in the 90s we were taught that these names were meant to save space in the symbol table because at one time space was so limited that naming your variable n rather than numElementsInArray would have an impact

  • GodIsNull@feddit.de
    161·
    1 year ago

    i for index or iteration. Using j, k, l… in loops signals (imho) that there is most likely an outer loop and the one using j, k, l are nested. x and y of course are carthesian coordinates . n is used as amount of substance in SI-unit-system, m is mass, maybe thats why it is used as amount of items in a set (Menge).

    Programming computers have started to solve mathematical problems and math already used these symbols for centuries(?), so why you should change them? They are well established even in simple school mathematics. And at the end of the day a computer is nothing more than a calculator.

    • Knusper@feddit.de
      4·
      1 year ago

      I’ve hardly ever looped over indices after college. For-each loops solve 99% of real-world problems in a better way.

  • youRFate@feddit.de
    51·
    1 year ago

    Usually variables like that can be avoided with itterators nowadays. If they can’t I like to use idx, if they are nested I name them after what they index, like idx_rows, idx_cols.

  • kent_ehEnglish
    4·
    1 year ago

    I prefer to use K in for loops, but that’s just me.