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Branching vs array indexing

This is a discussion on Branching vs array indexing within the General Discussions forums, part of the Community Boards category; Originally Posted by smokeyangel Didn't sound crazy until I looked up the command pattern -- looks, err, rather heavyweight! wildcard_seven's ...

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by smokeyangel
    Didn't sound crazy until I looked up the command pattern -- looks, err, rather heavyweight!
    wildcard_seven's particular suggestion is basically the same idea as mapping indices to function pointers in an array, except that the table has keys that are not necessarily just numbers, and they map to function objects rather than function pointers.
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    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
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    Quote Originally Posted by laserlight View Post
    wildcard_seven's particular suggestion is basically the same idea as mapping indices to function pointers in an array, except that the table has keys that are not necessarily just numbers, and they map to function objects rather than function pointers.
    Oh... ok. That sounds more reasonable. I was looking at Command pattern - Wikipedia, the free encyclopedia as wildcard_seven mentioned "command pattern" and it's what he said, but with a load more decoupling.

    I can see the advantages in looking up functions with a Key rather than an index. I'm afraid I don't see the advantage of function objects over function pointers. [edit] but I see a google search has a few results on this matter.

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    Function objects allow the compiler to inline functions bwcause the compiler can see the functions. With pointers, it cannot do this.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
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    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

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    Master Apprentice phantomotap's Avatar
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    Function objects allow the compiler to inline functions bwcause the compiler can see the functions.
    That's true, but in this case the suggestion involved putting instances of a function object with abstract interfaces into a table so the compiler wouldn't be able to see the functions.

    Soma

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