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> Being very much a kid (at heart at least), I'll wager the question: what's the case against declaring variables as you need them? There's not really one, it'

by saghm 4y ago

> Being very much a kid (at heart at least), I'll wager the question: what's the case against declaring variables as you need them? There's not really one, it's just a joke about how some languages used to work. > Also, at the top of which scope are you supposed to declare variables, function scope, class scope, ... somewhere else? In C, you used to have to declare all local variables at the top of the function rather than throughout the body.

jfoutz 4y ago
What? you want your compiler to backtrack and recalculate all the stack offsets? Just say how many bytes a call needs up front! Kids today, acting like computer time is free.
xenomachina 4y ago
> In C, you used to have to declare all local variables at the top of the function rather than throughout the body. This is true, but support for block-scoped (as opposed to function-scoped) variable declarations was added to C a long time ago. Every version of ANSI C supports them, and this stack exchange answer, https://softwareengineering.stackexchange.com/a/300274/19196 https://softwareengineering.stackexchange.com/a/300274/19196, suggests that support was added to K&R C since at least 1978.
- saghm 4y ago
  Hmm, interesting! I might be remembering wrong, but I remember within the last decade being told by a coworker that it was required for proper Windows support, but maybe that was just an old version of Visual Studio from XP or something that no longer needs to be supported.
  - spc476 4y ago
    And C99 allows you to declare variables anywhere in the function (much like C++).
    - saghm 4y ago
      I remember that the reason my coworker had said that they couldn't use local variables declared anywhere in functions for their Windows code was due to not supporting C99, but maybe that was just due to some external constraint rather than a Windows-specific one (like some customer needing them to support pre-C99 code or something).
      - xenomachina 4y ago
        Even C89 supports block-level variable declarations. I think many C programmers are unaware of this, though, and mistakenly think that declarations are function-level only.

by saghm 4y ago

jfoutz 4y ago

What? you want your compiler to backtrack and recalculate all the stack offsets? Just say how many bytes a call needs up front! Kids today, acting like computer time is free.

xenomachina 4y ago

> In C, you used to have to declare all local variables at the top of the function rather than throughout the body. This is true, but support for block-scoped (as opposed to function-scoped) variable declarations was added to C a long time ago. Every version of ANSI C supports them, and this stack exchange answer, https://softwareengineering.stackexchange.com/a/300274/19196 https://softwareengineering.stackexchange.com/a/300274/19196, suggests that support was added to K&R C since at least 1978.

saghm 4y ago
Hmm, interesting! I might be remembering wrong, but I remember within the last decade being told by a coworker that it was required for proper Windows support, but maybe that was just an old version of Visual Studio from XP or something that no longer needs to be supported.
- spc476 4y ago
  And C99 allows you to declare variables anywhere in the function (much like C++).
  - saghm 4y ago
    I remember that the reason my coworker had said that they couldn't use local variables declared anywhere in functions for their Windows code was due to not supporting C99, but maybe that was just due to some external constraint rather than a Windows-specific one (like some customer needing them to support pre-C99 code or something).
    - xenomachina 4y ago
      Even C89 supports block-level variable declarations. I think many C programmers are unaware of this, though, and mistakenly think that declarations are function-level only.