Subtracting Strings

This is a discussion on Subtracting Strings within the C Programming forums, part of the General Programming Boards category; i had a question. if i needed to subtract two strings( which contain lower case letter words) from one another, ...

  1. #1
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    Subtracting Strings

    i had a question. if i needed to subtract two strings( which contain lower case letter words) from one another, how would i approach this or do this? i mean subtract as in:
    i have two strings each contains lower case letters and i want to subtract one from the other as in,subtract 'evil' from 'festival' and getting the characters 'fsta' in return.
    any help would be appreciated.

  2. #2
    Registered User claudiu's Avatar
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    Not sure if there is such a function in string.h don't think so but you can make your own, however this is a typical pain in the ass in C string manipulation.

    this is the algorithm:

    iterate through the second array (the one you are subtracting){
    get next letter;
    iterate through the first array(the one you are subtracting from){
    find first occurance of letter;
    make another string from array1 without it;
    use pointers and make first array become the new array;
    EDIT: break;
    }
    }
    Last edited by claudiu; 03-16-2010 at 07:21 PM.

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    Or you could just print all characters from "festival" that is not the characters e,v,i,l.

    What should happen if not all characters are present? Or if a character appear more than once? You might have to make some changes based on the answers of those questions.

  4. #4
    and the hat of sweating
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    Look for a C regex library online. There should be thousands of them.
    "I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008

    "the internet is a scary place to be thats why i dont use it much." - billet, 03/17/2010

  5. #5
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    Yeah, and you might even have one installed. I have a regex.h that is part of BSD standard library.

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