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submitted 1 year ago* (last edited 1 year ago) by ashishlotake@mastodon.social to c/linux@lemmy.ml
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[-] fubo@lemmy.world 72 points 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.world 32 points 1 year ago* (last edited 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 points 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.

[-] GregoryTheGreat@programming.dev 20 points 1 year ago

So I’ve been an engineer doing code ports to newer versions of Fortran. I never knew why that was at the top of every file. Thank you.

[-] relative_iterator@sh.itjust.works 11 points 1 year ago

Interesting. I assumed i for iterator.

[-] fubo@lemmy.world 23 points 1 year ago

i, j, k are commonly used as subscripts in linear algebra, too.

i^2 = j^2 = k^2 = ijk =-1

this post was submitted on 26 Aug 2023
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