View Poll Results: do you use goto in c/c++/c#/etc programming?

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  • Everything should flow. No goto.

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  • I'm still wondering what this has to do with logic gates.

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addition

This is a discussion on addition within the A Brief History of Cprogramming.com forums, part of the Community Boards category; i read somewhere that computers add using some combination of logic gates, and that the only way multiplication could be ...

  1. #1
    Just because ygfperson's Avatar
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    Talking addition

    i read somewhere that computers add using some combination of logic gates, and that the only way multiplication could be done is through addition. is this true, and if so, how?
    ty in advance

  2. #2
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    think of multiplication like this:

    9 multiplied by 8 means 9 eight times over,
    so 9 * 8 == 9+9+9+9+9+9+9+9.

    starX
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  3. #3
    B26354 Deckard's Avatar
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    I believe you're thinking of boolean logic gates. You may be interested in the explination provided here.
    Jason Deckard

  4. #4
    Just because ygfperson's Avatar
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    about multiplication: what if the number were big? back when i had a tandy 1000ex(8.077 mhz, 1984 i think) basic could do a for i=1 to 5000, next loop in one second. is there some sort of help the processor gets?

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    and the hat of wrongness Salem's Avatar
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    Hamster without a wheel iain's Avatar
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    the multiplication cannot actually be done by a computer due to the logic systems it uses, so the multipolication is carried out by bit-shifting and addition
    Monday - what a way to spend a seventh of your life

  7. #7
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    Well, multiplication and loops are different beasts.

    For multiplication: Technically, you could just have a multiplication table in your CPU, but the way I learned it, it's a combination of shifts, additions, and perhaps subtractions.

    For loops: You can think of increment or decrement operators as even more basic than addition and subtraction. Loops are very important, so much that loop commands are commonly a part of a processor's architecture.
    Callou collei we'll code the way
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  8. #8
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    or you may be interested in wasting your time clicking the link provided here

  9. #9
    B26354 Deckard's Avatar
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    Originally posted by Sean
    or you may be interested in wasting your time clicking the link provided here
    That is a stroke of pure genius which should be prominently displayed at the beginning of the FAQ. :)
    Jason Deckard

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